Resin composition and multi-layer structures

ABSTRACT

Provided is a resin composition comprising 1-99% by weight of a modified ethylene-vinyl alcohol copolymer (C) having an ethylene content of 5-55 mol %, which contains a specific structural unit (I) in an amount of 0.3-40 mol % and can be obtained by reacting an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) having a molecular weight of not more than 500, and 1-99% by weight of a thermoplastic resin (T1) other than (C). Moreover, a multilayer structure in which the resin composition and a thermoplastic resin (T2) are laminated is also provided. Thus, a resin composition superior in barrier properties, transparency, stretchability, flexibility, flexing resistance and interlayer adhesiveness and various kinds of molded articles made thereof are provided.

TECHNICAL FIELD

The present invention relates to a resin composition comprising amodified ethylene-vinyl alcohol copolymer and a thermoplastic resinother than the copolymer. Moreover, the invention relates to a resincomposition which can be obtained by subjecting a modifiedethylene-vinyl alcohol copolymer and an elastomer to a dynamiccrosslinking treatment. Moreover, the invention relates also to varioustypes of molded articles and multilayer structures comprising theseresin compositions and to their applications.

BACKGROUND ART

An ethylene-vinyl alcohol copolymer, which henceforth may be abbreviatedas EVOH, is superior in transparency and gas barrier property, but ithas defect of being poor in stretchability, flexibility and flexingresistance. Known is a method of blending a flexible resin such as anethylene-vinyl acetate copolymer and an ethylene-propylene copolymer toan EVOH to improve the defect. However, this method has a defect thatthe transparency deteriorates greatly.

On the other hand, JP-A-63-230757 discloses a resin compositioncomprising 94-30 parts by weight of EVOH (A) having an ethylene contentof 20-45 mol % and a degree of saponification of 96 mol % or more and6-70 parts by weight of EVOH (B) having an ethylene content of 24-49 mol% and a degree of saponification of less than 96 mol %, wherein theethylene content of (B) is greater by at least 4 mol % than that of (A)and the degree of saponification of (A) is greater by at least 3 mol %than that of (B) and wherein the ethylene contents and solubilityparameters of (A) and (B) satisfy a specific relation. This resincomposition is reported to be superior in heat high-speedstretchability.

JP-A-50-12186 discloses a method for producing a modified EVOH with animproved mold-workability, the method being characterized by reacting0.01-0.8 parts by weight of polyfunctional epoxy compound with 100 partsby weight of EVOH having an ethylene content of 20-90 mol % and a degreeof saponification of 95% or more. This published specification alsodiscloses that such a modified EVOH can be mixed with the other resinssuch as unmodified EVOH and polyolefin.

However, in a method of blending a soft resin other than EVOH to EVOH,it is difficult for a resulting resin composition to have satisfactorystretchability, flexibility and flexing resistance and satisfactorytransparency simultaneously. In addition, the gas barrier property isalso deteriorated. Moreover, the resin composition disclosed in theabove-cited JP-A-63-230757 does not necessarily have satisfactoryflexibility or satisfactory flexing resistance.

In JP-A-50-12186, an improvement in neck-in (a phenomenon that a productwidth becomes narrower than die slit width) which occurs when an EVOH isshaped into a film through a T-die is disclosed as an improvement inmold-workability. However, there is no description about the improvementin stretchability, flexibility and flexing resistance, which is theobject of the present invention. Moreover, the EVOH resulting from areaction with a specific amount of multifunctional epoxy compound or aresin composition containing the same, which are disclosed in theabove-cited publication cannot demonstrate effects of improvingstretchability, flexibility and flexing resistance. Furthermore, in thecase of using a polyfunctional epoxy compound, it is difficult toproduce an EVOH whose amount of modification with an epoxy compound iswithin the specific range specified in the present invention.

An object of the present invention is to provide a resin compositionsuperior in barrier properties, transparency, stretchability,flexibility, flexing resistance and interlayer adhesiveness and abarrier material comprising the same. In addition, the present inventionintends to provide various types of molded articles comprising such aresin composition.

DISCLOSURE OF THE INVENTION

The above-mentioned objects can be achieved by providing a resincomposition comprising 1-99% by weight of a modified ethylene-vinylalcohol copolymer (C) having an ethylene content of 5-55 mol % andcontaining 0.3-40 mol % of the following structural unit (I) and 1-99%by weight of a thermoplastic resin (T1) other than (C):

wherein R¹, R², R³ and R⁴ denote a hydrogen atom, an aliphatichydrocarbon group having 1-10 carbon atoms, an alicyclic hydrocarbongroup having 3-10 carbon atoms or an aromatic hydrocarbon group having6-10 carbon atoms; R¹, R², R³ and R⁴ may be the same group or maydiffer; R³ and R⁴ may be combined together; and R¹, R² R³ and R⁴may havea hydroxyl group, a carboxyl group or a halogen atom.

It is preferable that both R¹ and R² be hydrogen atoms. It is morepreferable that one of R³ and R⁴ be an aliphatic hydrocarbon grouphaving 1-10 carbon atoms and the other be a hydrogen atom. It is stillmore preferable that one of R³ and R⁴ be a substituent represented by(CH₂)_(i)OH, wherein i is an integer of 1-8, and the other be a hydrogenatom.

In addition, the above-mentioned objects are also achieved by providinga resin composition comprising 1-99% by weight of a modifiedethylene-vinyl alcohol copolymer (C) obtained by reacting anethylene-vinyl alcohol copolymer (A) with a monofunctional epoxycompound (B) having a molecular weight of not more than 500 and 1-99% byweight of a thermoplastic resin (T1) other than (C).

It is preferable that the modified ethylene-vinyl alcohol (C) have amelting point of not higher than 160° C. It is also preferable that thethermoplastic resin (T1) have an oxygen transmission rate at 20° C. and65% RH of not more than 1000 cc·20 μm/m²·day·atm and that the resincomposition have an oxygen transmission rate at 20° C. and 65% RH of notmore than 100 cc·20 μm/m²·day·atm.

That the thermoplastic resin (T1) is an ethylene-vinyl alcohol copolymer(F) having an ethylene content of 5-55 mol % and being free of saidstructural unit (I) is one preferable embodiment of the presentinvention. In such an event, it is more preferable that the resincomposition comprise 1-50% by weight of the modified ethylene-vinylalcohol copolymer (C) and 50-99% by weight of the ethylene-vinyl alcoholcopolymer (F). It is more preferable that the difference between theethylene content of the modified ethylene-vinyl alcohol copolymer (C)and the ethylene content of the ethylene-vinyl alcohol copolymer (F) be2-30 mol %.

That the thermoplastic resin (T1) is a polyolefin (G) is also onepreferable embodiment of the present invention. In such an event, it ismore preferable that the resin composition comprise 10-60% by weight ofthe modified ethylene-vinyl alcohol copolymer (C) and 40-90% by weightof the polyolefin (G). That the thermoplastic resin (T1) comprises apolyolefin (G) and a compatibilizer (H) is also one preferableembodiment of the present invention.

The above-mentioned objects are also achieved by providing a resincomposition obtained by mixing 100 parts by mass of a modifiedethylene-vinyl alcohol copolymer (C) containing 0.3-40 mol % of afollowing structural unit (I), 5-900 parts by mass of an elastomer (J)having a functional group capable of reacting with the followingcrosslinking agent (K) and 0.05-30 parts by weight, based on 100 partsby weight of the elastomer (J), of a crosslinking agent (K) under meltcondition and performing a dynamic crosslinking treatment:

wherein R¹, R², R³ and R⁴ denote a hydrogen atom, an aliphatichydrocarbon group having 1-10 carbon atoms, an alicyclic hydrocarbongroup having 3-10 carbon atoms or an aromatic hydrocarbon group having6-10 carbon atoms; R¹, R², R³ and R⁴ may be the same group or maydiffer; R³ and R⁴ may be combined together; and R¹, R², R³ and R⁴ mayhave a hydroxyl group, a carboxyl group or a halogen atom.

It is preferable that the modified ethylene-vinyl alcohol copolymer (C)be one which is obtained by reacting an ethylene-vinyl alcohol copolymer(A) with a monofunctional epoxy compound (B) having a molecular weightof not more than 500. It is preferable that a particle of a crosslinkedelastomer (J) having a diameter of 0.1-30 μm be dispersed in a matrix ofthe modified ethylene-vinyl alcohol copolymer (C).

In such an event, it is preferable that the functional group capable ofreacting with the crosslinking agent be at least one functional groupselected from the group consisting of a hydroxyl group, an amino group,an alkylamino group, an epoxy group, an ether group, a carboxyl group,an ester group, an amide group, a bromine group, a group having astructure of dicarboxylic anhydride, a boronic acid group, aboron-containing group that is convertible to a boronic acid group inthe presence of water and a double bond. It is also preferable that theelastomer (J) be a block copolymer which has a functional group capableof reacting the crosslinking agent (K) and which comprises a vinylaromatic polymer block and a conjugate diene polymer block.

One preferable embodiment of the present invention is a barrier materialcomprising any of the above-mentioned resin compositions. A moldedarticle, an extrusion molded article, a film, a sheet, a oriented film,a thermoformed article, a heat shrinkable film, a pipe, a hose, anextrusion blow molded article, a container, a packing for a container, aflexible packaging material, and a material for a packaging food andbeverage are all preferable embodiments of the present invention.

A multilayer structure in which a layer of any of the above-mentionedresin compositions and a layer of another material, such as athermoplastic resin (T2) are laminated, is also a preferable resincomposition of the present invention. In such an event, it is preferablethat the thermoplastic resin (T2) be at least one selected from thegroup consisting of polyolefin, polyamide, polyester, polystyrene,polyurethane, polyvinylidene chloride, polyvinyl chloride,polyacrylonitrile and polycarbonate. It is also preferable that thethermoplastic resin (T2) be an elastomer.

A coextrusion film, coextrusion sheet, multilayer pipe, multilayer hose,pipe for hot water circulation and coextrusion blow molded containercomprising the above-mentioned multilayer structure are all preferableembodiments. Moreover, a coinjection blow molded container comprisingthe above-mentioned multilayer structure is also one preferableembodiment. In this event, a coinjection blow molded container in whichthe thermoplastic resin (T2) is at least one selected from the groupconsisting of polyester, polypropylene and polyethylene is aparticularly preferable embodiment.

The present invention is described in detail below.

The present invention is a resin composition comprising 1-99% by weightof a modified ethylene-vinyl alcohol copolymer (C) having an ethylenecontent of 5-55 mol % and containing 0.3-40 mol % of the followingstructural unit (I) and 1-99% by weight of a thermoplastic resin (T1)other than (C):

wherein R¹, R², R³ and R⁴ denote a hydrogen atom, an aliphatichydrocarbon group having 1-10 carbon atoms (e.g. an alkyl group and analkenyl group), an alicyclic hydrocarbon group having 3-10 carbon atoms(e.g. a cycloalkyl group and a cycloalkenyl group) and an aromatichydrocarbon group having 6-10 carbon atoms (e.g. a phenyl group); R¹,R², R³ and R⁴ may be the same group or may differ; R³ and R⁴ may becombined together, provided that the case where both R³ and R⁴ arehydrogen atoms is excluded; and R¹, R², R³ and R⁴ may have other groups,for example, a hydroxyl group, a carboxyl group and a halogen atom.

The modified EVOH (C) used in the present invention is a modifiedethylene-vinyl alcohol copolymer (C) having an ethylene content of 5-55mol % and containing 0.3-40 mol % of the structural unit (I) shownabove.

In a more preferable embodiment, both R¹ and R² are hydrogen atoms. In astill more preferable embodiment, both R¹ and R² are hydrogen atoms andone of R³ and R⁴ is an aliphatic hydrocarbon group having 1-10 carbonatoms and the other is a hydrogen atom. Preferably, the aliphatichydrocarbon group is an alkyl group or an alkenyl group. From aviewpoint of attaching great importance to the gas barrier propertiesrequired when the modified EVOH (C) is used as a barrier material, it ismore preferable that one of R³ and R⁴ be a methyl group or an ethylgroup and the other be a hydrogen atom.

In addition, from a view point of the gas barrier properties requiredwhen the modified EVOH (C) is used as a barrier material, it ispreferable also that one of R³ and R⁴ be a substituent represented by(CH₂)_(i)OH, wherein i is an integer of 1-8, and the other be a hydrogenatom. When much importance is attached to the gas barrier properties asa barrier material, in the substituent represented by (CH₂)_(i)OH, i ispreferably an integer of 1-4, more preferably 1 or 2, and still morepreferably 1.

The amount of the structure unit (I) contained in the modified EVOH (C)must fall within the range of 0.3-40 mol %. The lower limit of theamount of the structure unit (I) is preferably not less than 0.5 mol %,more preferably not less than 1 mol %, and still more preferably notless than 2 mol %. On the other hand, the upper limit of the amount ofthe structure unit (I) is not more than 35 mol %, more preferably notmore than 30 mol %, and still more preferably not more than 25 mol %. Amodified EVOH (C) superior simultaneously in gas barrier properties,transparency, stretchability, flexibility and flexing resistance can beobtained when the amount of the structure unit (I) contained thereinfalls within the range mentioned above.

The ethylene content of the modified EVOH (C) is preferably 5-55 mol %.From a viewpoint where the modified EVOH (C) of the present inventionbecomes superior in stretchability, flexibility and flexing resistance,the lower limit of the ethylene content of the modified EVOH (C) is morepreferably not less than 10 mol %, still more preferably not less than20 mol %, particularly preferably not less than 25 mol %, and morepreferably not less than 31 mol %. On the other hand, from a viewpointof the gas barrier properties of the modified EVOH (C) of the presentinvention, the upper limit of the ethylene content of the modified EVOH(C) is more preferably not more than 50 mol %, still more preferably notmore than 45 mol %. When the ethylene content is less than 5 mol %, themelt moldability may become poor, whereas when it exceeds 55 mol %, thegas barrier properties may be insufficient.

The constituents of the modified EVOH (C) other than the structure units(I) and the ethylene units are mainly vinyl alcohol units. The vinylalcohol units are usually vinyl alcohol units which had not reacted withmonofunctional epoxy compounds (B)contained in a starting EVOH (A).Unsaponified vinyl acetate units which may be contained in the EVOH (A)are usually contained in the modified EVOH (C) as they are. Measurementsof NMR and melting point showed that the modified EVOH (C) is a randomcopolymer which contains these constituents. Furthermore, otherconstituents may also be contained unless the object of the presentinvention is adversely affected.

A preferable melt flow rate (MFR) (measured at 190° C. under a load of2160 g) of the modified EVOH (C) of the present invention is 0.1-30 g/10min, more preferably 0.3-25 g/10 min, and still more preferably 0.5-20g/10 min. It is noted that when the melting point is about 190° C. orover 190° C., the measurements are carried out under a load of 2160 g attwo or more temperatures not lower than the melting point. The resultsare plotted, in a semilog graph, with reciprocals of absolutetemperatures as abscissa against logarithms of MFRs as ordinate and thepreferable MFR is represented by an extrapolation to 190° C.

The method for producing the modified EVOH (C) is not limitedparticularly. The method that the present inventors recommend is amethod in which the modified EVOH (C) is obtained by reacting anethylene vinyl alcohol copolymer (A) with a monofunctional epoxycompound (B) having a molecular weight of not more than 500.

In addition, the object the present invention intends to solve is alsoachieved by providing a resin composition comprising 1-99% by weight ofa modified ethylene-vinyl alcohol copolymer (C) obtained by reacting anethylene-vinyl alcohol copolymer (A) with a monofunctional epoxycompound (B) having a molecular weight of not more than 500 and 1-99% byweight of a thermoplastic resin (T1) other than (C).

Substances suitable as an EVOH (A) used as a raw material of themodified EVOH (C) to be mixed with the thermoplastic resin (T1) in thepresent invention are described below. An EVOH (A) suitably used as araw material of the modified EVOH (C) used in the production of theresin composition resulting from a dynamic crosslinking treatment, whichis another preferable embodiment of the present invention, will bedescribed later.

As the EVOH (A) used as a raw material of the modified EVOH (C),preferred is one obtained by saponifying an ethylene-vinyl estercopolymer. A typical vinyl ester used in the production of EVOH is vinylacetate. However, other fatty acid vinyl esters (e.g. vinyl propionateand vinyl pivalate) may also be employed. Unless the object of thepresent invention is adversely affected, it is also permitted tocopolymerize other comonomers, for example, α-olefins such as propylene,butylene, isobutene, 4-methyl-1-pentene, 1-hexene and 1-octene;unsaturated carboxylic acids or esters thereof such as (meth)acrylicacid, methyl (meth)acrylate and ethyl (meth)acrylate; vinylsilanecompounds such as vinyltrimethoxysilane; unsaturated sulfonic acids orsalts thereof; alkylthiols; and vinylpyrrolidones such asN-vinylpyrrolidone.

When an EVOH resulting from copolymerization with a vinylsilane compoundas a comonomer component is used as the EVOH (A), it is preferable thatthe EVOH contain that component copolymerized in an amount of 0.0002-0.2mol %. When the EVOH contains a vinylsilane compound as a comonomercomponent in an amount within that range, the compatibility in meltviscosity between a substrate resin and the modified EVOH (C) may beimproved in coextrusion molding, thereby enabling to produce homogeneousmultilayer coextrusion film articles. In particular, when using asubstrate resin with a high melt viscosity, it becomes easy to obtainhomogeneous multilayer coextrusion film articles. The vinylsilanecompound includes, for example, vinyltrimethoxysilane,vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane andγ-methacryloxypropylmethoxysilane. Above all, preferred arevinyltrimethoxysilane and vinyltriethoxysilane.

The ethylene content of the EVOH (A) for use in the present invention ispreferably 5-55 mol %. From a viewpoint where the modified EVOH (C) ofthe present invention becomes superior in stretchability, flexibilityand flexing resistance, the lower limit of the ethylene content of theEVOH (A) is more preferably not less than 10 mol %, still morepreferably not less than 20 mol %, particularly preferably not less than25 mol %, and more preferably not less than 31 mol %. On the other hand,from a viewpoint of the gas barrier property of the modified EVOH (C),the upper limit of the ethylene content of the EVOH (A) is morepreferably not more than 50 mol %, still more preferably not more than45 mol %. When the ethylene content is less than 5 mol %, the meltmoldability may become poor, whereas when it exceeds 55 mol %, the gasbarrier property may be insufficient. When the EVOH (A) for use in theinvention comprises a mixture of two or more EVOHs of different ethylenecontents, an average value calculated from the blend proportions inweight of the EVOHs shall be the ethylene content of the EVOH (A).

The degree of saponification of the vinyl ester moiety in the EVOH (A)for use in the present invention is preferably not less than 90%. Thedegree of saponification of the vinyl ester moiety is more preferablynot less than 95%, still more preferably not less than 98%, and mostsuitably not less than 99%. A degree of saponification of less than 90%may result in an unsatisfactory thermostability which may result in easyformation of gels and pimples in molded articles, as well as indeterioration of gas barrier properties, especially gas barrierproperties at high humidity. When the EVOH (A) comprises a mixture oftwo or more EVOHs of different degrees of saponification, an averagevalue calculated from the blend proportions in weight of the EVOHs shallbe the degree of saponification of the EVOH (A).

The ethylene content and the degree of saponification of the EVOH (A)can be determined by the nuclear magnetic resonance (NMR) analysis.

Furthermore, an EVOH containing a boron compound blended therein mayalso be employed as the EVOH (A) unless the object of the presentinvention is adversely affected. The boron compound includes, forexample, boric acids, borates, salts of boric acids and boron hydrides.Concretely, the boric acids include orthoboric acid, metaboric acid,tetraboric acid, etc.; the borates include triethyl borate, trimethylborate, etc.; the salts of boric acids include alkali metal salts andalkaline earth metal salts of various boric acids such as thosementioned above, as well as borax, etc. Of those compounds, preferred isorthoboric acid, which may be referred to as boric acid hereinafter.

When the EVOH (A) containing a boron compound blended therein isemployed as the EVOH (A), its boron compound content is preferably20-2000 ppm and more preferably 50-1000 ppm in terms of boron element.Blending the boron compound in an amount within such ranges can affordan EVOH (A) the torque variation of which is restrained during itsmelting by heating. However, if the boron compound content is smallerthan 20 ppm, such an effect will be reduced, whereas if larger than 2000ppm, a resulting EVOH will gel easily and it may be of poor moldability.

In addition, an EVOH (A) containing a phosphoric acid compound may beemployed as the EVOH (A). This may successfully stabilize the qualities(e.g. coloration) of the resin. The phosphoric acid compound for use inthe present invention is not restricted particularly. Various acids,such as phosphoric acid and phosphorous acid, and their salts may beused. The salts of phosphoric acids may be in any form of primaryphosphate, secondary phosphate and tertiary phosphate, but primaryphosphates are preferred. The cation species is not also specificallyrestricted. However, alkali metal salts are preferred. Of these salts,sodium dihydrogen phosphate and potassium dihydrogen phosphate arepreferable. When an EVOH (A) containing a phosphoric acid compound isused, the content of the phosphoric acid compound is preferably not morethan 200 ppm, more preferably 5-100 ppm, and most preferably 5-50 ppm interms of phosphate radical.

However, when the EVOH (A) and a monofunctional epoxy compound (B) arereacted together in the presence of a catalyst (D) containing an ion ofa metal which belongs to any of Groups 3-12 of the periodic table asdescribed later, it is desirable that the content of the phosphoric acidcompound be as small as possible because the salts of phosphoric acidwill deactivate the catalyst. In this case, the content of thephosphoric acid compound in the EVOH (A) is preferably not more than 200ppm, more preferably not more than 100 ppm, and most preferably not morethan 50 ppm in terms of phosphate radical.

Moreover, as described later, the modified EVOH (C) is obtainedpreferably by carrying out a reaction between an EVOH (A) and amonofunctional epoxy compounds (B) having a molecular weight of not morethan 500 in an extruder. During the reaction, the EVOH is exposed to aheating condition. If the EVOH (A) contains an excess amount of alkalimetal salt and/or alkaline earth metal salt at this time, the resultingmodified EVOH (C) may suffer from coloration. In addition, problems suchas a decrease in viscosity of the modified EVOH (C) may arise, resultingin deterioration of moldability thereof. In addition, when a catalyst(D) is used as described later, it is desirable that the amounts ofthose salts to be added be as small as possible because they willdeactivate the catalyst (D).

In order to avoid the above-mentioned problems, it is preferable thatthe content of the alkali metal salt contained in the EVOH (A) be notmore than 50 ppm in terms of the metal elements. In a more preferableembodiment, the content of the alkali metal salt contained in the EVOH(A) is not more than 30 ppm, more preferably not more than 20 ppm interms of the metal elements. From the same viewpoint, the content of thealkaline earth metal salt contained in the EVOH (A) is preferably notmore than 20 ppm, more preferably not more than 10 ppm, and still morepreferably not more than 5 ppm in terms of the metal elements. It ismost preferable that substantially no alkaline earth metal salt becontained in the EVOH (A).

In addition, an EVOH containing a heat stabilizer, an antioxidant or thelike incorporated therein may be used as the EVOH (A) unless the objectof the present invention is adversely affected.

The EVOH (A) for use in the present invention preferably has anintrinsic viscosity of not less than 0.06 L/g. The intrinsic viscosityof the EVOH (A) is more preferably within the range of 0.07-0.2 L/g,still more preferably 0.075-0.15 L/g, and particularly preferably0.080-0.12 L/g. If the intrinsic viscosity of the EVOH (A) is less than0.06 L/g, the stretchability, flexibility and flexing resistance maydeteriorate. On the other hand, if the intrinsic viscosity of the EVOH(A) exceeds 0.2 L/g, gels and pimples may form easily in a moldedarticle comprising the modified EVOH (C).

A preferable melt flow rate (MFR) (measured at 190° C. under a load of2160 g) of the EVOH (A) for use in the present invention is 0.1-30 g/10min, more preferably 0.3-25 g/10 min, and still more preferably0.5-20g/10 min. It is noted that when a melting point is about 190° C.or over 190° C., the measurements are carried out under a load of 2160 gat two or more temperatures not lower than the melting point. Theresults are plotted, in a semilog graph, with reciprocals of absolutetemperatures as abscissa against logarithms of MFRs as ordinate and thepreferable MFR is represented by an extrapolation to 190° C. Two or moreEVOHs of different MFRs may be mixed and used.

The monofunctional epoxy compound (B) having a molecular weight of notmore than 500 for use in the present invention must be a monofunctionalepoxy compound. In other words, it must be an epoxy compound which hasonly one epoxy group in its molecule. When a polyfunctional epoxycompound of two or more functionalities is used, the effect of thepresent invention can not be obtained. It is to be noted that during theproduction of the monofunctional epoxy compound, a very small amount ofpolyfunctional epoxy compound may be contained. Unless the effect of thepresent invention is adversely affected, a monofunctional epoxy compoundcontaining a very small amount of polyfunctional epoxy compound can beused as the monofunctional epoxy compound (B) having a molecular weightof not more than 500 in the present invention.

The monofunctional epoxy compound (B) having a molecular weight of notmore than 500 for use in the present invention is not limitedparticularly. Specifically, compounds represented by the followingformulae (III) through (IX) can be used suitably:

wherein R⁵, R⁶, R⁷, R⁸ and R⁹ each represent a hydrogen atom, analiphatic hydrocarbon group (e.g. alkyl group, alkenyl group or thelike) having 1-10 carbon atoms, an alicyclic hydrocarbon group (e.g.cycloalkyl group, cycloalkenyl group or the like) having 3-10 carbonatoms, and an aromatic hydrocarbon group having 6-10 carbon atoms (e.g.phenyl group or the like); and i, j, k, l and m each denote an integerof 1-8.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by formula (III) includeepoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane,2,3-epoxybutane, 3-methyl-1,2-epoxybutane, 1,2-epoxypentane,2,3-epoxypentane, 3-methyl-1,2-epoxypentane, 4-methyl-1,2-epoxypentane,4-methyl-2,3-epoxypentane, 3-ethyl-1,2-epoxypentane, 1,2-epoxyhexane,2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxyhexane,4-methyl-1,2-epoxyhexane, 5-methyl-1,2-epoxyhexane,3-ethyl-1,2-epoxyhexane, 3-propyl-1,2-epoxyhexane,4-ethyl-1,2-epoxyhexane, 5-methyl-1,2-epoxyhexane,4-methyl-2,3-epoxyhexane, 4-ethyl-2,3-epoxyhexane,2-methyl-3,4-epoxyhexane, 2,5-dimethyl-3,4-epoxyhexane,3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyheptane,5-methyl-1,2-epoxyheptane, 6-methyl-1,2-epoxyheptane,3-ethyl-1,2-epoxyheptane, 3-propyl-1,2-epoxyheptane,3-butyl-1,2-epoxyheptane, 4-ethyl-1,2-epoxyheptane,4-propyl-1,2-epoxyheptane, 5-ethyl-1,2-epoxyheptane,4-methyl-2,3-epoxyheptane, 4-ethyl-2,3-epoxyheptane,4-propyl-2,3-epoxyheptane, 2-methyl-3,4-epoxyheptane,5-methyl-3,4-epoxyheptane, 5-ethyl-3,4-epoxyheptane,2,5-dimethyl-3,4-epoxyheptane, 2-methyl-5-ethyl-3,4-epoxyheptane,1,2-epoxyheptane, 2,3-epoxyheptane, 3,4-epoxyheptane, 1,2-epoxyoctane,2,3-epoxyoctane, 3,4-epoxyoctane, 4,5-epoxyoctane, 1,2-epoxynonane,2,3-epoxynonane, 3,4-epoxynonane, 4,5-epoxynonane, 1,2-epoxydecane,2,3-epoxydecane, 3,4-epoxydecane, 4,5-epoxydecane, 5,6-epoxydecane,1,2-epoxyundecane, 2,3-epoxyundecane, 3,4-epoxyundecane,4,5-epoxyundecane, 5,6-epoxyundecane, 1,2-epoxydodecane,2,3-epoxydodecane, 3,4-epoxydodecane, 4,5-epoxydodecane,5,6-epoxydodecane, 6,7-epoxydodecane, epoxyethylbenzene,1-phenyl-1,2-epoxypropane, 3-phenyl-1,2-epoxypropane,1-phenyl-1,2-epoxybutane, 3-phenyl-1,2-epoxybutane,4-phenyl-1,2-epoxybutane, 1-phenyl-1,2-epoxypentane,3-phenyl-1,2-epoxypentane, 4-phenyl-1,2-epoxypentane,5-phenyl-1,2-epoxypentane, 1-phenyl-1,2-epoxyhexane,3-phenyl-1,2-epoxyhexane, 4-phenyl-1,2-epoxyhexane,5-phenyl-1,2-epoxyhexane and 6-phenyl-1,2-epoxyhexane.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (IV) includemethyl glycidyl ether, ethyl glycidyl ether, n-propyl glycidyl ether,isopropyl glycidyl ether, n-butyl glycidyl ether, isobutyl glycidylether, tert-butyl glycidyl ether, 1,2-epoxy-3-pentyloxypropane,1,2-epoxy-3-hexyloxypropane, 1,2-epoxy-3-heptyloxypropane,1,2-epoxy-3-octyloxypropane, 1,2-epoxy-3-phenoxypropane,1,2-epoxy-3-benzyloxypropane, 1,2-epoxy-4-methoxybutane,1,2-epoxy-4-ethoxybutane, 1,2-epoxy-4-propoxybutane,1,2-epoxy-4-butoxybutane, 1,2-epoxy-4-pentyloxybutane,1,2-epoxy-4-hexyloxybutane, 1,2-epoxy-4-heptyloxybutane,1,2-epoxy-4-phenoxybutane, 1,2-epoxy-4-benzyloxybutane,1,2-epoxy-5-methoxypentane, 1,2-epoxy-5-ethoxypentane,1,2-epoxy-5-propoxypentane, 1,2-epoxy-5-butoxypentane,1,2-epoxy-5-pentyloxypentane, 1,2-epoxy-5-hexyloxypentane,1,2-epoxy-5-phenoxypentane, 1,2-epoxy-6-methoxyhexane,1,2-epoxy-6-ethoxyhexane, 1,2-epoxy-6-propoxyhexane,1,2-epoxy-6-butoxyhexane, 1,2-epoxy-6-heptyloxyhexane,1,2-epoxy-7-methoxyheptane, 1,2-epoxy-7-ethoxyheptane,1,2-epoxy-7-propoxyheptane, 1,2-epoxy-7-butyloxyheptane,1,2-epoxy-8-methoxyheptane, 1,2-epoxy-8-ethoxyheptane,1,2-epoxy-8-butoxyheptane, glycidol, 3,4-epoxy-1-butanol,4,5-epoxy-1-pentanol, 5,6-epoxy-1-hexanol, 6,7-epoxy-1-heptanol,7,8-epoxy-1-octanol, 8,9-epoxy-1-nonanol, 9,10-epoxy-1-decanol and10,11-epoxy-1-undecanol.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (V) includeethylene glycol monoglycidyl ether, propanediol monoglycidyl ether,butanediol monoglycidyl ether, heptanediol monoglycidyl ether,hexanediol monoglycidyl ether, heptanediol monoglycidyl ether andoctanediol monoglycidyl ether.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (VI) include3-(2,3-epoxy)propoxy-1-propene, 4-(2,3-epoxy)propoxy-1-butene,5-(2,3-epoxy)propoxy-1-pentene, 6-(2,3-epoxy)propoxy-1-hexene,7-(2,3-epoxy)propoxy-1-heptene and 8-(2,3-epoxy)propoxy-1-octene.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (VII) include3,4-epoxy-2-butanol, 2,3-epoxy-1-butanol, 3,4-epoxy-2-pentanol,2,3-epoxy-1-pentanol, 1,2-epoxy-3-pentanol,2,3-epoxy-4-methyl-1-pentanol, 2,3-epoxy-4,4-dimethyl-1-pentanol,2,3-epoxy-1-hexanol, 3,4-epoxy-2-hexanol, 4,5-epoxy-3-hexanol,1,2-epoxy-3-hexanol, 2,3-epoxy-4-methyl-1-hexanol,2,3-epoxy-4-ethyl-1-hexanol, 2,3-epoxy-4,4-dimethyl-1-hexanol,2,3-epoxy-4,4-diethyl-1-hexanol, 2,3-epoxy-4-methyl-4-ethyl-1-hexanol,3,4-epoxy-5-methyl-2-hexanol, 3,4-epoxy-5,5-dimethyl-2-hexanol,3,4-epoxy-2-heptanol, 2,3-epoxy-1-heptanol, 4,5-epoxy-3-heptanol,2,3-epoxy-4-heptanol, 1,2-epoxy-3-heptanol, 2,3-epoxy-1-octanol,3,4-epoxy-2-octanol, 4,5-epoxy-3-octanol, 5,6-epoxy-4-octanol,2,3-epoxy-4-octanol, 1,2-epoxy-3-octanol, 2,3-epoxy-1-nonanol,3,4-epoxy-2-nonanol, 4,5-epoxy-3-nonanol, 5,6-epoxy-4-nonanol,3,4-epoxy-5-nonanol, 2,3-epoxy-4-nonanol, 1,2-epoxy-3-nonanol,2,3-epoxy-1-decanol, 3,4-epoxy-2-decanol, 4,5-epoxy-3-decanol,5,6-epoxy-4-decanol, 6,7-epoxy-5-decanol, 3,4-epoxy-5-decanol,2,3-epoxy-4-decanol and 1,2-epoxy-3-decanol.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (VIII) include1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxycycloheptane,1,2-epoxycyclooctane, 1,2-epoxycyclononane, 1,2-epoxycyclodecane,1,2-epoxycycloundecane and 1,2-epoxycyclododecane.

Examples of the monofunctional epoxy compound (B) having a molecularweight of not more than 500 represented by the formula (IX) include3,4-epoxycyclopentene, 3,4-epoxycyclohexene, 3,4-epoxycycloheptene,3,4-epoxyyclooctene, 3,4-epoxycyclononene, 1,2-epoxycyclodecene,1,2-epoxycycloundecene and 1,2-epoxycyclododecene.

Epoxy compounds having 2-8 carbon atoms are particularly preferred asthe monofunctional epoxy compound (B) having a molecular weight of notmore than 500 used for the present invention. The number of carbon atomsof the monofunctional epoxy compound (B) is preferably 2-6, morepreferably 2-4 from the viewpoints of easiness of the handling of acompound and reactivity with EVOH (A). Moreover, it is preferable thatthe monofunctional epoxy compound (B) be a compound represented by theformula (III) or (IV). From the viewpoints of the reactivity with EVOH(A) and the gas barrier properties of a modified EVOH (C) to beobtained, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethaneand glycidol are particularly preferable. Above all, epoxypropane andglycidol are preferable. In the applications in which sanitariness isrequired, such as food packaging, drink packaging and drug packaging, itis desirable to use 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane andepoxyethane as the epoxy compound (B). Above all, epoxypropane ispreferably employed.

A modified EVOH (C) is obtained by reacting the EVOH (A) and themonofunctional epoxy compound (B). A preferable mixing ratio of the EVOH(A) and the monofunctional epoxy compound (B) is 1-50 parts by weight of(B) to 100 parts by weight of (A), more preferably 2-40 parts by weightof (B) to 100 parts by weight of (A), and particularly preferably 5-35parts by weight of (B) to 100 parts by weight of (A).

The method for producing the modified EVOH (C) by reacting the EVOH (A)with the monofunctional epoxy compound (B) having a molecular weight ofnot more than 500 is not limited particularly; examples of preferablemethods include a production method in which the EVOH (A) and themonofunctional epoxy compound (B) are reacted together in a solution,and a production method in which the EVOH (A) and the monofunctionalepoxy compound (B) are reacted together within an extruder.

In the production method using a solution reaction, the modified EVOH(C) is obtained by reacting the monofunctional epoxy compound (B) with asolution of the EVOH (A) in the presence of an acid catalyst or analkali catalyst. In addition, the modified EVOH (C) can be produced alsoby dissolving the EVOH (A) and the monofunctional epoxy compound (B) ina reaction solvent and then performing a heat treatment. As the reactionsolvent, preferable are polar aprotic solvents, which are good solventsof the EVOH (A), such as dimethylsulfoxide, dimethylformamide,dimethylacetamide and N-methylpyrrolidone.

The reaction catalyst includes acid catalysts such as p-toluenesulfonicacid, methanesulfonic acid, trifluoromethane sulfonic acid, sulfuricacid and boron trifluoride and alkali catalysts such as sodiumhydroxide, potassium hydroxide, lithium hydroxide and sodium methoxide.Among these, acid catalysts are preferably employed. The amount of thecatalyst is appropriately 0.0001-10 parts by weight to 100 parts byweight of the EVOH (A). The reaction temperature is appropriately withinthe range of room temperature to 150° C.

In the production method in which the EVOH (A) and the monofunctionalepoxy compound (B) are reacted together within an extruder, there are noparticular limitations for extruder to use, but it is preferable toreact the EVOH (A) and the monofunctional epoxy compound (B) at atemperature of about 180-300° C. by use of a single screw extruder, twinscrew extruder or a multi-screw extruder having two or more screws. Asdescribed below, during the reaction performed within an extruder, it ispreferable to employ a relatively low melting temperature in the case ofcausing a catalyst (D) to be present. On the other hand, when nocatalyst (D) is employed, a desirable temperature is about 200-300° C.

When a twin screw extruder or a multi-screw extruder having two or morescrews is used, modification of the screw structure easily increases thepressure within the reaction section and makes it possible to perform areaction between the EVOH (A) and the monofunctional epoxy compound (B)efficiently. In the case of using a single screw extruder, it ispossible to increase the pressure within the reaction section byconnecting two or more extruders and disposing a valve in a resinpassageway between the extruders. Alternatively, the production may becarried out by connecting two or more twin screw extruders ormulti-screw extruders having two or more screws.

In comparison of the production method by a solution reaction to thatusing a reaction within an extruder, the method using a solutionreaction requires a solvent to dissolve the EVOH (A) and also requiresrecovery and removal of the solvent after the reaction. Therefore, sucha method is to have a complicated process. In order to enhance thereactivity between the EVOH (A) and the monofunctional epoxy compound(B), it is desirable to hold the reaction system under heat and/orpressure conditions. In comparison to the solution reaction, it is easy,in the reaction within an extruder, to maintain the heat and/or pressureconditions of the reaction system. From such a viewpoint, the reactionwithin an extruder is of great merit.

Furthermore, when performing the reaction between the EVOH (A) and themonofunctional epoxy compound (B) by a solution reaction, it isn'tnecessarily easy to control the reaction and, therefore, the reactionmay proceed excessively. In other words, although the modified EVOH (C)having the structural unit (I) is obtained as a result of the reactionbetween the EVOH (A) and the monofunctional epoxy compound (B), aproduct having a structural unit different than that specified in thepresent invention may be obtained through a further reaction of ahydroxyl group contained in the structural unit (I) with amonofunctional epoxy compound (B). Specifically, when the monofunctionalepoxy compound (B) is ethylene oxide, the above-mentioned excessiveproceeding of the reaction will result in the formation of an EVOHhaving a structural unit (II) shown below:

wherein n denotes a natural number of 1 or more.

The present inventors studied and made it clear that the increase in theratio of the above-mentioned structural unit (II) contained which unitis different from the structural unit (I) specified in the presentinvention, results in the reduction in the gas barrier property of themodified EVOH (C) to be obtained. Furthermore, they found that theoccurrence of such a side reaction could be restrained effectively whenthe reaction between the EVOH (A) and the monofunctional epoxy compound(B) is performed in an extruder. From such a viewpoint, preferred is themethod in which the modified EVOH (C) is produced by performing thereaction between the EVOH (A) and the monofunctional epoxy compound (B)in an extruder.

In addition, in the method using a solution reaction, heating thereaction system may cause the vaporization of the monofunctional epoxycompound (B) to the outside of the system because the monofunctionalepoxy compound (B) having a molecular weight of not more than 500 usedin the present invention does not always have a high boiling point.However, it is possible to inhibit the vaporization of themonofunctional epoxy compound (B) to the outside of the system byreacting the EVOH (A) with the monofunctional epoxy compound (B) in anextruder. In particular, when the monofunctional epoxy compound (B) issupplied under pressure during its addition to the extruder, it ispossible to increase the reactivity between the EVOH (A) and themonofunctional epoxy compound (B) and, at the same time, to inhibitremarkably the vaporization of the monofunctional epoxy compound (B) tothe outside of the system.

The method of mixing the EVOH (A) and the monofunctional epoxy compound(B) during the reaction in an extruder is not limited particularly.Preferable examples include a method in which the monofunctional epoxycompound (B) is sprayed to the EVOH (A) before being fed to the extruderand a method in which the EVOH (A) is fed to the extruder and is broughtinto contact with the monofunctional epoxy compound (B) in the extruder.Among these, preferred is the method in which the EVOH (A) is fed intoan extruder and then it is brought into contact with the monofunctionalepoxy compound (B) within the extruder from a viewpoint that thevaporization to the monofunctional epoxy compound (B) to the outside ofthe system can be inhibited. In addition, the position where themonofunctional epoxy compound (B) is added to the extruder is optional.However, from the viewpoint of reactivity between the EVOH (A) with theepoxy compound (B), it is desirable to add the monofunctional epoxycompound (B) to molten EVOH (A).

A production method using a reaction between the EVOH (A) and themonofunctional epoxy compound (B) within an extruder which isrecommended by the present inventor comprises (1) a step of melting theEVOH (A), (2) a step of adding the monofunctional epoxy compound (B) and(3) a step of removing unreacted monofunctional epoxy compound (B)through a vent or the like. From the viewpoint of performing a reactionsmoothly, it is preferable to remove moisture and oxygen from thesystem. For this purpose, moisture and oxygen may be removed through avent or the like before the addition of the monofunctional epoxycompound (B) to the extruder.

In addition, in the step of adding the monofunctional epoxy compound(B), it is preferable to supply the monofunctional epoxy compound (B)under pressure as described previously. At this time, if the pressure isnot high enough, the reactivity may decrease and problems such asvariation in discharge rate will arise. A necessary pressure variesgreatly depending upon the boiling point of the monofunctional epoxycompound (B) and the extrusion temperature, but it is, in usual,preferably within the range of 0.5-30 MPa and more preferably within therange of 1-20 MPa.

In the production method of the present invention, it is preferable tomelt-knead the EVOH (A) and the monofunctional epoxy compound (B) in anextruder in the presence of a catalyst (D) containing an ion of a metalwhich belongs to Groups 3-12 of the periodic table. To cause thecatalyst (D) containing an ion of a metal which belongs to Groups 3-12of the periodic table to be present makes it possible to react the EVOH(A) with the monofunctional epoxy compound (B) efficiently even if themelt-kneading is carried out at a lower temperature. In other words, itis possible to obtain a highly modified EVOH (C) easily through amelt-kneading at a relatively low temperature. The EVOH is a resin themelt stability of which at high temperatures is not very good.Therefore, from the viewpoint that the degradation of a resin can beprevented, it is desirable that melt kneading can be carried out at sucha low temperature. When the EVOH (A) and the monofunctional epoxycompound (B) are reacted together without using the catalyst (D), aresulting modified EVOH (C) tends to have an MFR lower than that of thestarting EVOH (A). However, when using the catalyst (D), the MFR doesnot change very much.

The catalyst (D) used in the present invention contains an ion of ametal which belongs to Groups 3-12 of the periodic table. What is themost important for the metal ion used for the catalyst (D) is to have amoderate Lewis acidity. From this standpoint, ions of metals whichbelong to Groups 3-12 of the periodic table are used. Among these, ionsof metals which belong to Group 3 or 12 of the periodic table arepreferable due to their moderate Lewis acidities; ions of zinc, yttriumand gadolinium are more preferable. Above all, a catalyst (D) containinga zinc ion is most suitable because it has an extremely high catalyticactivity and a modified EVOH (C) superior in thermostability would beobtained.

The ion of a metal which belongs to Groups 3-12 of the periodic table isadded preferably in an amount of 0.1-20 μmol/g, in terms of molar numberof metal ion based on the weight of the EVOH (A). When a too largeamount of ion is added, the EVOH may gelate during its melt-kneading.Therefore, the amount of the ion is more preferably not more than 10μmol/g. On the other hand, when a too small amount of ion is added, nosatisfactory effect of the addition of the catalyst (D) may be obtained.Therefore, the amount of the ion is more preferably not less than 0.5μmol/g. It is to be noted that an appropriate amount of the ion of ametal which belongs to Groups 3-12 of the periodic table may varydepending upon the kind of the metal to be employed and the kind of theanion described later and, therefore, should be adjusted appropriatelyin view of these factors.

The anion species in the catalyst (D) containing an ion of a metal whichbelongs to Groups 3-12 of the periodic table is not limitedparticularly, but it is desirable for the catalyst to contain amonovalent anion the conjugate acid of which is a strong acid as strongas or stronger than sulfuric acid. This is because an anion theconjugate acid of which is a strong acid is usually hard to react with amonofunctional epoxy compound (B) because of its low nucleophilicity andthe anion can prevent the loss of catalytic activity caused byconsumption of anionic species through a nucleophilic reaction. Inaddition, that is also because when having such an anion as a counterion, the catalyst (D) has an improved Lewis acidity and, therefore, itscatalytic activity is improved.

Examples of the monovalent anion the conjugate acid of which is a strongacid as strong as or stronger than sulfuric acid include sulfonate ionssuch as methanesulfonate ion, ethanesulfonate ion,trifluoromethanesulfonate ion, benzenesulfonate ion and toluenesulfonateion; halide ion such as chloride ion, bromide ion and iodide ion;perchlorate ion; anions having four or more fluorine atoms such astetrafluoroborate ion (BF₄ ⁻), hexafluorophosphate ion (PF₆ ⁻),hexafluoroarsinate ion (AsF₆ ⁻) and hexafluoroantimonate ion; ions oftetraphenyl borate derivatives such as tetrakis(pentafluorophenyl)borate ion; and ions of carborane derivatives astetrakis(3,5-bis(trifluoromethyl)phenyl) borate,bis(undecahydride-7,8-dicarbaundecaborate) cobalt (III) ion,bis(undecahydride-7,8-dicarbaundecaborate) iron (III) ion.

When using a catalyst (D) including an anionic species such as, forexample, hexafluorophosphate or tetrafluoroborate of the anionic speciesmentioned above, the anion species itself is thermostable and has a verylow nucleophilicity. However, the anion species may react with a hydroxygroup in an EVOH to form hydrogen fluoride, giving a bad influence tothe thermostability of a resin. In addition, carborane derivative ionsof cobalt or the like do not react with EVOH and their anionic speciesthemselves are thermostable. However, they are very expensive.

A sulfonate ion is preferable as the anionic species of the catalyst (D)because it does not react with an EVOH, it is thermostable as an anionicspecies itself and also it is appropriately priced. Examples of suitablesulfonic acid ions include methanesulfonate ion,trifluoromethanesulfonate ion, benzenesulfonate ion and toluenesulfonateion. Trifluoromethanesulfonate ion is most suitable.

The following formula (X) shows a presumed mechanism of the reactionbetween the EVOH (A) and the monofunctional epoxy compound (B) when azinc ion and a trifluoromethanesulfonate ion are used, respectively, asthe cationic species and the anionic species of the catalyst (D).

Briefly speaking, it is presumed that the oxygen atom of the epoxy groupof the monofunctional epoxy compound (B) coordinates to the zinc ionbonding to the hydroxyl group of the EVOH in the form of a metalalkoxide and, via a 6 membered-ring transition state, the epoxy ringopens. Because the conjugate acid of a trifluoromethanesulfonate ion,which is the counter ion of a zinc ion in the transition state, is astrong acid, the Lewis acidity of the zinc ion becomes high and thecatalytic activity improves. On the other hand, because thetrifluoromethanesulfonate ion itself which is present as a counter ionnever reacts with a hydroxyl group of the EVOH or an epoxy group of themonofunctional epoxy compound (B) and is thermostable. Therefore, thering-opening reaction proceeds smoothly without causing any sidereaction.

As described above, it is preferable that the catalyst (D) used in thepresent invention contain a monovalent anion the conjugate acid of whichis a strong acid as strong as or stronger than sulfuric acid, but it isnot necessary that all the anionic species in the catalyst (D) be sameanionic species. It is rather desirable that the catalyst (D) alsocontains an anion the conjugate acid of which is a weak acid. If thereaction mechanism represented by the formula (X) is true, when an EVOHreacts with a catalyst (D) to form a metal alkoxide, one of the anionsis liberated as a conjugate acid into the system. If this is a strongacid, it may react with a monofunctional epoxy compound (B) and at thesame time it may give an adverse effect to the melt stability of theEVOH.

Examples of the anion the conjugate ion of which is a weak acid includealkyl anion, aryl anion, alkoxide, aryloxy anion, carboxylate andacetylacetonato and its derivative. Above all, alkoxide, carboxylate andacetylacetonato and its derivative are suitably employed.

It is desirable that the molar number of the anion the conjugate acid ofwhich is as strong as or stronger than sulfuric acid be 0.2-1.5 timesthe molar number of the metal ions in the catalyst(D). When theabove-mentioned molar ratio is less than 0.2 times, the catalyticactivity may be insufficient. The molar ratio is more preferably notless than 0.3 times, and still more preferably not less than 0.4 times.On the other hand, when the above-mentioned molar ratio exceeds 1.5times, the EVOH may gelate. The molar ratio is more preferably not morethan 1.2 times. The molar ratio is most preferably 1 time. In addition,when the EVOH (A), which is a raw material, contains an alkali metalsalt such as sodium acetate, the molar number of the anion the conjugateacid of which is as strong as or stronger than sulfuric acid may beincreased by an amount corresponding to the anion neutralized andconsumed by the salt.

The method for preparing the catalyst (D) is not limited particularly,but an example of a preferable method is a method in which a compound ofa metal which belongs to Groups 3-12 of the periodic table is dissolvedor dispersed in a solvent and then a strong acid (e.g. sulfonic acid)the conjugate acid of which is as strong as or stronger than sulfuricacid is added to the resulting solution or suspension. Examples of thecompound of a metal which belongs to Group 3-12 of the periodic table tobe used as a raw material include alkyl metal, aryl metal, metalalkoxide, metal aryloxide, metal carboxylate and metal acetylacetonato.When the strong acid is added to the solution or suspension of thecompound of a metal which belongs to Group 3-12 of the periodic table,it is preferable that the strong acid be added in small portions. Thethus obtained solution containing the catalyst (D) may be introduceddirectly to an extruder.

As the solvent in which the compound of the metal which belongs to Group3-12 of the periodic table is dissolved or dispersed, organic solvents,especially ether solvents, are preferable. This is because it is hard toreact even at a temperature in the extruder and at the same time theyhave a good solubility of the metal compound. Examples of the ethersolvents include dimethyl ether, diethyl ether, tetrahydrofuran,dioxane, 1,2-dimethoxyethane, diethoxyethane, diethylene glycol dimethylether and trienthylene glycol dimethyl ether. As a solvent to be used,preferred are those which are superior in solubility of metal compounds,are of relatively low boiling point, and can be removed almostcompletely through a vent formed in an extruder. From this standpoint,diethylene glycol dimethyl ether, 1,2-dimethoxyethane andtetrahydrofuran are particularly preferable.

In addition, in the above-mentioned method for the preparation of thecatalyst (D), an ester of a strong acid (e.g. sulfonate) may be usedinstead of the strong acid to add. The ester of a strong acid may causeno reaction with the metal compound at room temperature because itgenerally has a reactivity lower than that of the strong acid itself.However, when it is introduced into an extruder of high temperaturewhich is held at about 200° C., a catalyst (D) having an activity in theextruder can be formed.

As a method for preparing the catalyst (D), the alternate methoddescribed below may be adopted. First, a water-soluble compound of ametal which belongs to Group 3-12 of the periodic table and a strongacid (e.g. sulfonic acid) the conjugate acid of which is as strong as orstronger than sulfuric acid are mixed in an aqueous solution to form aaqueous catalyst solution. At this time, the aqueous solution maycontain an appropriate amount of alcohol. An EVOH (A) containing thecatalyst (D) can be obtained by contacting the resulting aqueouscatalyst solution into contact with the EVOH (A) and then drying.Specifically, a preferable method is one in which pellets of the EVOH(A), especially porous hydrous pellets, are immersed in the aqueouscatalyst solution. In this case, the dry pellets thus obtained may beintroduced into an extruder.

When a catalyst (D) is used, it is preferable to set the temperature inthe extruder to 180-250° C. In this case, the catalyst (D) is presentduring the reaction between the EVOH (A) and the monofunctional epoxycompound (B). The reaction between the EVOH (A) and the monofunctionalepoxy compound (B) can, therefore, be allowed to proceed efficientlyeven if melt-kneading is carried out at a relatively low temperature.When the temperature exceeds 250° C., EVOH may deteriorate; thetemperature is more preferably not higher than 240° C. On the otherhand, when the temperature is lower than 180° C., the reaction betweenthe EVOH (A) and the monofunctional epoxy compound (B) may not proceedsufficiently; the temperature is more preferably not lower than 190° C.

The method for causing the catalyst (D) to be present when reacting theEVOH (A) and the monofunctional epoxy compound (B) together is notlimited particularly. A preferable method is one in which a solution ofthe catalyst (D) is prepared and then the solution is added to anextruder. The method for preparing the solution of the catalyst (D) isthe same as that mentioned previously. According to this method, can beachieved a productivity higher than that achieved by the alternatemethod described later. In addition, because the catalyst (D) can besupplied steadily, it is possible to stabilize the quality of products.The position where the solution of the catalyst (D) is introduced intoan extruder is not limited particularly. However, it is preferable toadd the solution at a position where the EVOH (A) is in a completelymolten state because the solution can be mixed uniformly. In particular,it is desirable to add the solution at or about the position where themonofunctional epoxy compound (B) is added. This is because when thecatalyst (D) and the monofunctional epoxy compound (B) are added almostsimultaneously, the degradation of the EVOH (A) resulting from theinfluence of the catalyst (D), which is a Lewis acid, can be kept to aminimum and a sufficient reaction time can be secured. Therefore, themost suitable way is to prepare a mixed liquid of a solution of thecatalyst (D) and the monofunctional epoxy compound (B) in advance,followed by adding it at a single position into an extruder.

An alternative method for causing the catalyst (D) to be present duringthe melt-kneading may be a method in which hydrous pellets of the EVOH(A) are immersed in a solution of the catalyst (D) and then dried. Whatwere described previously about the alternative method for thepreparation of the catalyst (D) are also applicable to this method. Inthis case, the resulting dry pellets are to be introduced into theextruder from a hopper. However, the problem is that an expensivecatalyst is disposed as waste liquid and this is liable to cause anincrease in cost. Another alternative method is a method comprisingimpregnating dried pellets with a catalyst in a liquid state or mixingdried pellets with a catalyst in a solid state and then, as required,drying the pellets. A problem with this method is that the increase ofthe number of steps is liable to result in the increase in cost. Inaddition, it is not necessarily easy to blend the catalyst uniformly. Inany of the above alternative methods, the EVOH (A) may deteriorate inthe course of melt-kneading under conditions where no monofunctionalepoxy compound (B) is present and only the catalyst (D), which is aLewis acid, is present.

As described above, to melt-knead the EVOH (A) and the monofunctionalepoxy compound (B) together in the presence of the catalyst (D) in anextruder is desirable. It is more desirable to add a catalystdeactivator (E) after the melt-kneading and then carry out additionalmelt-kneading. When the catalyst (D) is not deactivated, thethermostability of a modified EVOH (C) to be obtained may be poor andsome problems may arise in the use thereof depending upon theapplication.

The catalyst deactivator (E) to be used may be any one which is able toreduce the activity of the catalyst (D) as a Lewis acid and the kindthereof is not restricted particularly. Alkali metal salts are suitablyemployed. To deactivate a catalyst (D) containing a monovalent anion theconjugate acid of which is a strong acid as strong as or stronger thansulfuric acid, it is required to use an alkali metal salt containing ananion of an acid which is weaker than the conjugate acid of themonovalent anion. This is because when doing so, a counter ion of theion of a metal belonging to Group 3-12 of the periodic table whichconstitutes the catalyst (D) is replaced with an ion of a weaker acid,resulting in reduction in the Lewis acidity of the catalyst (D). Thecationic species of the alkali metal salt to be used for the catalystdeactivator (E) is not limited particularly and suitable examplesthereof include sodium salts, potassium salts and lithium salts. Theanionic species is not also limited particularly and suitable examplesthereof include carboxylates, phosphates and phosphonates.

Even if a salt such as sodium acetate and dipotassium hydrogenphosphateis used as the catalyst deactivator (E), the heat stability is improvedconsiderably but may be insufficient depending upon the application.This is assumed to be because the ion of the metal which belongs toGroup 3-12 of the periodic table still has some activity as a Lewis acidand, therefore, can serve as a catalyst with respect to decompositionand gelation of a modified EVOH (C). As a method for further improvingthis problem, it is desirable to add a chelating agent which stronglycoordinates to an ion of a metal which belongs to Group 3-12 of theperiodic table. Such a chelating agent can coordinate to the metal ionstrongly and, as a result, it can eliminate the Lewis acidity of the ionalmost completely and can provide a modified EVOH (C) superior inthermostability. In addition, when the chelating agent is an alkalimetal salt, it can neutralize a strong acid which is a conjugate acid ofan anion contained in the catalyst (D) as described previously.

Examples of suitable chelating agents to be used as the catalystdeactivator (E) include hydroxycarboxylates, aminocarboxylates andaminophosphonates. Specific examples of the hydroxycarboxylates includedisodium citrate, disodium tartrate and disodium malate. Examples of theaminocarboxylates include trisodium nitrilotriacetate, disodiumethylenediaminetetraacetate, trisodium ethylenediaminetetraacetate,tripotassium ethylenediaminetetraacetate, trisodiumdiethylenetriaminepentaacetate, trisodium1,2-cyclohexanediaminetetraacetate, monosodium ethylenediaminediacetate,monosodium N-(hydroxyethyl)iminodiacetate. Examples of theaminophosphonates include hexasodium nitrilotrismethylenephosphonate andoctasodium ethylenediaminetetra(methylenephosphonate). Above all,polyaminopolycarboxylic acids are suitable and alkali metal salts ofethylenediaminetetraacetic acid are most suitable in view of performanceand cost. A presumed reaction mechanism in the case of using trisodiumethylenediaminetetraacetate is shown in the following formula (XI).

The amount of the catalyst deactivator (E) to be added is not limitedparticularly and may be adjusted appropriately depending upon the kindof the metal ion contained in the catalyst (D) and the number ofcoordination sites of the chelating agent. It is suitable to set theamount so that the ratio (E/D) of the molar number of the catalystdeactivator (E) to the molar number of the metal ion contained in thecatalyst (D) may become 0.2-10. When the ratio (E/D) is less than 0.2,the catalyst (D) may not be deactivated sufficiently; the ratio ispreferably not less than 0.5, more preferably not less than 1. On theother hand, when the ratio (E/D) exceeds 10, a resulting modified EVOH(C) may get colored and the production cost may increase; the ratio ispreferably not more than 5, more preferably not more than 3.

The method for introducing the catalyst deactivator (E) into an extruderis not limited particularly, but in order to disperse it uniformly, itis preferable to introduce the catalyst deactivator (E) in the form of asolution thereof to a modified EVOH (C) in a molten state. Taking thesolubility of the catalyst deactivator (E), the influence to theperipheral environment, etc. into consideration, it is preferable to addit in the form of an aqueous solution.

The position where the catalyst deactivator (E) is added to the extrudermay be any position where the EVOH (A) and the monofunctional epoxycompound (B) have been melt-kneaded in the presence of the catalyst (D).However, it is preferable to add the catalyst deactivator (E) aftermelt-kneading the ethylene-vinyl alcohol copolymer (A) and themonofunctional epoxy compound (B) in the presence of the catalyst (D)and then removing unreacted monofunctional epoxy compound (B). This isbecause in the case of adding the catalyst deactivator (E) in the formof an aqueous solution as described previously, addition of the catalystdeactivator (E) before the removal of unreacted monofunctional epoxycompound (B) will result in incorporation of water into a monofunctionalepoxy compound (B) which is removed through a vent or the like and usedafter recovery, causing separation operations to require much labor. Inaddition, it is also preferable to remove water through a vent or thelike after addition of the aqueous solution of the catalyst deactivator(E).

In the production method of the present invention, an example of asuitable production process using a catalyst deactivator (E) is aprocess comprising the steps of:

-   (1) melting EVOH (A);-   (2) adding a mixture of a monofunctional epoxy compound (B) and a    catalyst (D);-   (3) removing unreacted monofunctional epoxy compound (B);-   (4) adding an aqueous solution of a catalyst deactivator (E); and-   (5) removing water under reduced pressure.

It is preferable that the modified EVOH (C) contain 0.1-20 μmol/g of anion of a metal which belongs to any of Groups 3-12 of the periodictable. The metal ion is one which may be contained as a catalyst residueformed when a catalyst (D) was used in the above-mentioned productionmethod. The kinds of preferable metal ions are the same as those recitedin the description previously made for the catalyst (D). The content ofthe ion is more preferably not less than 0.5 μmol/g, and more preferablynot more than 10 μmol/g.

In addition, the modified EVOH (C) preferably contains a sulfonic acidion. The sulfonic acid ion is one which may be contained as a catalystresidue formed when a catalyst (D) was used in the above-mentionedproduction method. The kinds of preferable sulfonic acid ions are thesame as those recited in the description previously made for thecatalyst (D). The content of the sulfonic acid ion is preferably 0.1-20μmol/g, and more preferably not less than 0.5 μmol/g and, in addition,more preferably not more than 10 μmol/g.

Furthermore, the content of an alkali metal ion in the modified EVOH (C)is preferably 1-50 times (in molar ratio) the content of the sulfonicacid ion. The alkali metal ion is one which may be contained as aresidue formed when the catalyst deactivator (E) was used in theabove-mentioned production method and may be contained due to derivationfrom the starting EVOH (A). If the content of the alkali metal ion isless than 1 time the content of the sulfonic acid ion, the deactivationof the catalyst (D) has not been performed sufficiently in theproduction process and, in such an occasion, some problem inthermostability of the modified EVOH (C) may arise. Therefore, thecontent of the alkali metal ion is more preferably at least 2 times. Onthe other hand, if the content of the alkali metal ion exceeds 50 timesthe content of the sulfonic acid ion, the modified EVOH (C) may getcolored. Therefore, the content of the alkali metal ion is preferably 30times at most.

To the modified EVOH (C), at least one substance selected from the groupconsisting of alkali metal salts, alkaline earth metal salts, carboxylicacids and phosphoric acid compounds may be added after the formation ofthe modified EVOH (C) through the reaction between the EVOH (A) and theepoxy compound (B). Generally, for the purpose of improvement in variousproperties of EVOH, e.g. improvement in adhesiveness and control ofcoloration, at least one substance selected from the group consisting ofalkali metal salts, alkaline earth metal salts, carboxylic acids andphosphoric acid compounds is often added to the EVOH as required.However, as described previously, the addition of various compoundsshown above may cause coloration, reduction in viscosity and the likeduring the reaction between the EVOH (A) and the epoxy compounds (B) inan extruder. Therefore, it is preferable to add at least one substanceselected from the group consisting of alkali metal salts, alkaline earthmetal salts, carboxylic acids and phosphoric acid compounds to amodified EVOH (C) resulting from a reaction between an EVOH (A) and anepoxy compound (B) followed by removal of the remaining epoxy compound(B) through a vent. When this addition method is adopted, the modifiedEVOH (C) is obtained without occurrence of problems such as colorationand reduction in viscosity.

The thus obtained modified EVOH (C) preferably has a melting point of160° C. or lower. This can minimize the melting point differencesbetween the modified EVOH (C) and resins having lower melting pointssuch as the polyolefin resin (G) and can lower the molding temperatureemployed when the resin composition is melt molded. The melting point ofthe modified EVOH (C) is preferably 150° C. or lower and more preferably140° C. or lower.

The resin composition of the present invention is a resin compositioncomprising from 1 to 99% by weight of the modified EVOH (C) and from 1to 99% by weight of a thermoplastic resin (T1) other than (C).

The thermoplastic resin (T1) which is incorporated to the modified EVOH(C) is not particularly restricted. Examples thereof include EVOH nothaving the aforementioned structural unit (I), polyolefin, polyamide,polyester, polystyrene, polyvinyl chloride, poly(meth)acrylic ester,polyvinylidene chloride, polyacetal, polycarbonate, polyvinyl acetate,polyurethane and polyacrylonitrile. Various kinds of copolymers may alsobe employed. Specifically, various types of thermoplastic resins whichare provided as examples of the thermoplastic resin (T2), describedlater, which is to be laminated to the resin composition of the presentinvention, can be employed.

The thermoplastic resin (T1) preferably has an oxygen transmission ratemeasured at 20° C. and 65% RH of 1000 cc·20 μm/m²·day·atm or lower. Thismeans that the volume of the oxygen which permeates a day through a 20μm thick film having an area of 1 m² under conditions where there is anoxygen pressure difference of 1 atm is 1000 ml or less when beingmeasured at 20° C. at 65% RH. Incorporation of a modified EVOH (C) canimprove the secondary processability, fatigue resistance and interlayeradhesiveness of the thermoplastic resin (T1), which inherently has goodbarrier properties. Examples of thermoplastic resin (T1) having anoxygen transmission rate measured at 20° C. at 65% RH of 1000 cc·20μm/m²·day·atm or less include EVOH free of the structural unit (I),polyamide, polyester, polyvinyl chloride, polyvinylidene chloride andpolyacrylonitrile. The oxygen transmission rate is more preferably notmore than 100 cc·20 μm/m²·day·atm and still more preferably not morethan 10 cc·20 μm/m²·day·atm.

In particular, it is preferable to use an EVOH (F) having an ethylenecontent of 5-55 mol % and being free of the structural unit (I) as thethermoplastic resin (T1). This is because it can greatly improve thesecondary processability, fatigue resistance, stretchability andinterlayer adhesiveness without seriously deteriorating the barrierproperties or transparency which are inherent to EVOH (F). Although thesame resins as the aforementioned EVOH (A) used as a raw material forthe modified EVOH (C) can be used as EVOH (F), they are appropriatelyselected depending on the composition of a modified EVOH (C) to beincorporated and the application of a resulting resin composition.

For example, from the viewpoint of heat stability, the ethylene contentof the EVOH (F) is preferably not less than 20 mol %, more preferablynot less than 25 mol %, and still more preferably not less than 27 mol%. From the viewpoint of gas barrier properties, the ethylene content ofthe EVOH (F) is preferably not more than 50 mol %, more preferably notmore than 45 mol %, and still more preferably not more than 38 mol %.The degree of saponification of the EVOH (F) is preferably 99% or more,and more preferably 99.5% or more.

The combination of the ethylene contents of the modified EVOH (C) andEVOH (F) is adjusted in according to the application and purpose of theresin composition. For example, the difference between the ethylenecontent of the modified EVOH (C) and that of the EVOH (F) is preferablyfrom 2 to 30 mol %. The difference is more preferably 5 mol % or more,but not more than 20 mol %.

In the case where there is a difference between the ethylene contents ofthe modified EVOH (C) and EVOH (F), when the ethylene content of themodified EVOH (C) is greater than that of the EVOH (F), the modifiedEVOH (C), which is excellent in flexibility, can be incorporated intothe EVOH (F), which is of good gas barrier properties, while thecharacteristics of the EVOH (F) are maintained. As a result, a resincomposition can be provided which is excellent in secondaryprocessabilities such as thermoformability and stretchability, orflexibility or flexing resistance, and gas barrier properties as well.This embodiment is one of the particularly useful embodiments.Conversely, in some cases, it is preferable that the ethylene content ofthe modified EVOH (C) be smaller than that of the EVOH (F). In suchcases, an advantage may be enjoyed when molding is intended to beperformed at low temperature because the melting points of both resinsare close.

On the other hand, in some cases, it is preferable that the differencebetween the ethylene contents of the modified EVOH (C) and EVOH (F) besmall. In such cases, the difference is preferably not more than 2 mol%. It is preferable to use a modified EVOH (C) and an EVOH (F) whichhave substantially the same ethylene content. When rendering thedifference between the ethylene contents of the modified EVOH (C) andEVOH (F) small, it is possible to obtain a resin composition excellentin barrier properties and transparency while improving flexibility,secondary processabilities, fatigue resistance or interlayeradhesiveness.

The resin composition comprising the modified EVOH (C) and the EVOH (F)is one comprising from 1 to 99% by weight of the modified EVOH (C) andfrom 1 to 99% by weight of the EVOH (F). It is preferable that the resincomposition comprise from 1 to 50% by weight of the modified EVOH (C)and from 50 to 99% by weight of the EVOH (F). In other words, it ispreferable that the unmodified EVOH (F) be a major ingredient and themodified EVOH (C) be a minor ingredient. This can impart flexibility andsecondary processability to the resin composition without causing aserious damage in gas barrier properties which the EVOH (F) inherentlyhas. In addition, this is also economically beneficial because themodified EVOH (C) requires much production cost than the unmodified EVOH(F). The content of the modified EVOH (C) is more preferably not lessthan 5% by weight, and still more preferably not less than 10% byweight. At this time, the content of the EVOH (F) is more preferably notmore than 95% by weight, and still more preferably not more than 90% byweight. On the other hand, the content of the modified EVOH (C) is morepreferably not more than 40% by weight, and still more preferably notmore than 30% by weight. At this time, the content of the EVOH (F) ismore preferably not less than 60% by weight, and still more preferablynot less than 70% by weight.

In addition, it is also preferable to use a polyolefin (G) as thethermoplastic resin (T1). The polyolefin (G) is of great usefulnessbecause of its superior mechanical properties, superior processabilitiesand low cost, but has low barrier properties. Incorporation of themodified EVOH (C) to the polyolefin (G) can improve the barrierproperties of the polyolefin (G) without causing serious damages inimpact resistance, fatigue resistance, processabilities and the like.

The polyolefin (G) used herein is not particularly restricted.Specifically, it is possible to employ various kinds of polyolefinswhich are provided as examples of the thermoplastic resin (T2),described later, which is to be laminated to the resin composition ofthe present invention. These polyolefins (G) may be used singly or as amixture of two or more of them. Among them, polypropylene, polyethylene,ethylene-propylene copolymer and ethylene-vinyl acetate copolymer arepreferably employed. In particular, polyethylene and polypropylene arepreferably employed.

The resin composition comprising the modified EVOH (C) and thepolyolefin (G) is one comprising from 1 to 99% by weight of the modifiedEVOH (C) and from 1 to 99% by weight of the polyolefin (G). It ispreferable that the resin composition comprise from 10 to 60% by weightof the modified EVOH (C) and from 40 to 90% by weight of the polyolefin(G). In other words, the resin composition containing the polyolefin (G)in an amount of not less than half thereof is preferable. This canimpart barrier properties to the resin composition without causingserious damages in mechanical performance and processability which thepolyolefin (G) inherently has. That is an economically advantageousincorporation proportion because the modified EVOH (C) requires aremarkably higher production cost than the polyolefin (G). The contentof the modified EVOH (C) is more preferably not less than 20% by weight.At this time, the content of the polyolefin (G) is not more than 80% byweight. On the other hand, the content of the modified EVOH (C) is morepreferably not more than 50% by weight. At this time, the content of thepolyolefin (G) is more preferably not less than 50% by weight.

In addition, it is also preferable to employ a compatibilizer (H) as thethermoplastic resin (T1). In such an occasion, a thermoplastic resinother than the modified EVOH (C) and the compatibilizer (H) is containedsimultaneously and the compatibilizer (H) is to improve thecompatibility of the thermoplastic resin with the modified EVOH (C). Thethermoplastic resin the compatibility of which with the EVOH (C) isimproved by the compatibilizer (H) is not particularly restricted, butpolyolefin (G), polystyrene and the like are preferable. In aparticularly preferable case, the thermoplastic resin the compatibilityof which is improved is a polyolefin (G). In other words, preferred is aresin composition in which a thermoplastic resin (T1) comprises thepolyolefin (G) and the compatibilizer (H).

Examples of a compatibilizer (H) preferably employed include polyolefin,polystyrene, diene polymer or copolymers thereof having a carboxyl group(including acid anhydride group), a boron-containing substituent, anepoxy group, an amino group and the like. Among them, those having acarboxyl group or a boron-containing substituent are preferred, examplesof which include those resulting from modification with maleicanhydride, those resulting from copolymerization with (meth)acrylicacid, and those resulting from introduction of boronic acid (ester)group. Polyolefin is preferable as a base polymer to which thesesubstituents are introduced. Particularly preferred are polyethylene andpolypropylene. Moreover, block copolymers of styrene and diene orhydrogenated products thereof are also examples of preferable basepolymers. Specific examples include carboxylic acid-modified polyolefinand boronic acid-modified polyolefin.

The amount of the compatibilizer (H) incorporated is preferably from 1to 20% by weight, and more preferably 20% by weight or more but not morethan 10% by weight.

Use of two or more kinds of resins which are preferable as thethermoplastic resin (T1) sometimes may result in a synergistic effectthereof. For example, a resin composition comprising the modified EVOH(C), the EVOH (F) and the polyolefin (G) has characteristics similar tothose of the aforementioned resin composition comprising the modifiedEVOH (C) and the polyolefin (G), but has an advantage in its lowerproduction cost. It is also preferable to incorporate the compatibilizer(H) in addition to the above three resins.

Various additives may be incorporated to the resin composition of thepresent invention as required. Examples of such additives includeantioxidants, plasticizers, heat stabilizers, ultraviolet absorbers,antistatic agents, lubricants, colorants, fillers or other highmolecular compound. These may be blended unless the effect of thepresent invention is adversely affected. The following are specificexamples of such additives.

Antioxidant: 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol,4,4′-thiobis-(6-t-butylphenol),2,2′-methylene-bis-(4-methyl-6-t-butylphenol),octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate,4,4′-thiobis-(6-t-butylphenol), etc.

Ultraviolet absorber: ethylene-2-cyano-3,3′-diphenyl acrylate,2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl) 5-chlorobenzotriazole,2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone,etc.

Plasticizer: dimethyl phthalate, diethyl phthalate, dioctyl phthalate,wax, liquid paraffin, phosphates, etc.

Antistatic agent: pentaerythritol monostearate, sorbitan monopalmitate,sulfated polyolefins, polyethylene oxide, Carbowax, etc.

Lubricant: ethylene bisstearoamide, butyl stearate, etc.

Colorant: carbon black, phthalocyanine, quinacridon, indoline, azopigments, red oxide, etc.

Filler: glass fiber, asbestos, vallastonite, calcium silicate, etc.

In addition, to the resin composition of the present invention, one kindor two or more kinds of hydrotalcite compound, hindered phenol type heatstabilizer, hindered amine type heat stabilizer, metal salt of higherfatty acid (e.g. calcium stearate and magnesium stearate) may be addedto an extent such that the effect of the present invention is notadversely affected (namely, 0.01-1% by weight) in order to improve meltstability or the like.

The method for blending the modified EVOH (C) and the thermoplasticresin (T1) in order to obtain the resin composition of the presentinvention is not particularly limited. For example, resin pellets may bedry blended and then subjected directly to melt molding. Morepreferably, resin pellets may be melt kneaded in a Banbury mixer, asingle or twin screw extruder or the like, pelletized and then subjectedto melt molding. For preventing deterioration of resin from proceedingduring the blending operation, it is desirable to extrude the resin atlow temperature while sealing the hopper inlet with nitrogen. Inaddition, it is preferable to make the dispersion of the resins fine andhomogeneous by use of an extruder with a high kneading intensity becausethe barrier properties and transparency are improved and the generationor admixture of gels or pimples is prevented.

The kneading is a significant operation in the present invention becauseeach resin ingredient is dispersed well in the resin composition. Themost suitable kneading machines for obtaining a composition having ahigh dispersion include continuous kneading machines such as continuousintensive mixers and kneading-type twin screw extruders (co-rotating orcounter-rotating). However, batch type kneading machines such as Banburymixers, intensive mixers and pressure kneaders are also available. Asanother type of continuous kneading machine, those utilizing a rotarydisc having a grinding mechanism such as a stone mill, for example, aKCK kneading extruder manufactured by KCK Co., Ltd. may be employed.Kneading machines commonly employed include those comprising a singlescrew extruder having a kneading section (e.g. Dulmage, CTM, etc.), orsimple kneading machines such as Brabender mixers.

Above all, the most suitable for the purpose of the present inventionare continuous intensive mixers. Commercially available models thereofinclude FCM from Farrel Corp., CIM from The Japan Steel Works, Ltd., andKCM, LCM and ACM from Kobe Steel, Ltd. In practical production, it ispreferable to employ an apparatus in which a single screw extruder isarranged under such a kneading machine, where kneading and extrusionpelletization are performed simultaneously. A twin screw kneadingextruder containing a kneading disc or a rotor for kneading, e.g. TEXfrom The Japan Steel Works, Ltd., ZSK from Werner & Pfleiderer Co., TEMfrom Toshiba Machine Co., Ltd. and PCM from Ikegai Ltd. are employed forthe purpose of kneading in the invention.

In use of such continuous kneading machines, the shapes of rotors anddiscs play important roles. In particular, a gap between a mixingchamber and a rotor chip or a disc chip, the gap being called a chipclearance, is important; neither a too narrow clearance nor a too wideclearance results in a resin composition having a satisfactorydispersion. The optimum chip clearance ranges from 1 to 5 mm.

The range of the rotation speed of the rotor of a kneading machine isfrom 100 to 1200 rpm, preferably from 150 to 1000 rpm, and still morepreferably from 200 to 800 rpm. The inner diameter (D) of the chamber ofa kneading machine is 30 mm or more, and preferably ranges from 50 to400 mm. The ratio of the chamber length (L) of the kneading machine tothe inner diameter, L/D, is preferably from 4 to 30. Only one kneadingmachine may be employed. Alternatively, two or more kneading machinesconnected together may be used. The longer the kneading time, the betterthe result. However, in view of prevention of resin deterioration oreconomical considerations, the kneading time ranges from 10 to 600seconds, preferably from 15 to 200 seconds, and optimally from 15 to 150seconds.

The resin composition of the present invention preferably has an oxygentransmission rate at 20° C. and 65% RH of not more than 100 cc·20μm/m²·day·atm. The upper limit of the oxygen transmission rate is morepreferably not more than 50 cc·20 μm/m²·day·atm, still more preferablynot more than 20 cc·20 μm/m²·day·atm, and particularly preferably notmore than 10 cc·20 μm/m²·day·atm. The resin composition of the presentinvention is suitably used as a barrier material and is particularlysuitably used as a container for food packaging because it is a resincomposition having such a low oxygen transmission rate.

In addition, the resin composition of the present invention preferablyhas a carbon dioxide gas transmission rate at 20° C. and 65% RH of notmore than 500 cc·20 μm/m²·day·atm. The upper limit of the carbon dioxidegas transmission rate is more preferably not more than 200 cc·20μm/m²·day·atm, still more preferably not more than 100 cc·20μm/m²·day·atm, and particularly preferably not more than 50 cc·20μm/m²·day·atm. The resin composition of the present invention issuitably used as a barrier material and is particularly suitably used asa container for carbonated beverage packaging because it is a resincomposition having such a low carbon dioxide gas transmission rate.

The resin composition of the present invention, in particular, a resincomposition comprising a modified EVOH (C) and an unmodified EVOH (F)preferably has a Young's modulus in a tensile strength/elongationmeasurement at 23° C. and 50% RH of not more than 200 kgf/mm², and morepreferably not more than 180 kgf/mm². Use of such a resin compositionmakes molded articles flexible which are obtained therefrom such assheets and films. In addition, the use makes these articles possible tobe secondarily processed well during the stretching or thermoformingthereof. In usual, the Young's modulus is not less than 50 kgf/mm².

It is preferable that the resin composition of the present invention, inparticular, a resin composition comprising a modified EVOH (C) and anunmodified EVOH (F) have a tensile strength at yield of from 4.0 to 10.0kgf/mm² and a tensile elongation at break of 200% or more in a tensilestrength/elongation measurement at 23° C. and 50% RH because moldedarticles obtained therefrom such as sheets and films demonstrate goodmoldability when being stretched or thermoformed. In usual, the tensileelongation at break is not more than 500%.

The resin composition comprising the modified EVOH (C) and thethermoplastic resin (T1) has been described above. A resin compositionobtainable through a dynamic crosslinking treatment, which is anotherembodiment of the present invention, is described below. The descriptionmade for the above-described resin composition composed of the modifiedEVOH (C) and the thermoplastic resin (T1) is applied, unless otherwisedescribed.

The resin composition obtainable through a dynamic crosslinkingtreatment, which is another embodiment of the present invention, is alsocalled a thermoplastic polymer composition because the composition has athermoplasticity though crosslinked grains are dispersed therein. Inother words, it is a resin composition obtainable by mixing 100 parts byweight of a modified EVOH (C) containing 0.3-40 mol % of the followingstructural unit (I), 5-900 parts by weight of an elastomer (J) having afunctional group capable of reacting with the following crosslinkingagent (K) and 0.05-30 parts by weight, based on 100 parts by weight ofthe elastomer (J), of a crosslinking agent (K) under melt condition andperforming a dynamic crosslinking treatment. In the followingdescription, this resin composition is sometimes referred to as adynamically crosslinked resin composition.

[In the formula, R¹, R², R³ and R⁴ denote a hydrogen atom, an aliphatichydrocarbon group having 1-10 carbon atoms (e.g. alkyl and alkenyl), analicyclic hydrocarbon group having 3-10 carbon atoms (e.g. cycloalkyland cycloalkenyl) or an aromatic hydrocarbon group having 6-10 carbonatoms (e.g. phenyl). R¹, R², R³ and R⁴ may be the same group or maydiffer. R³ and R⁴ may be combined together, unless both R³ and R⁴ arehydrogen atoms. R¹, R², R³ and R⁴ may have other groups than describedabove, e.g. a hydroxyl group, a carboxyl group and a halogen atom.]

Almost the same Modified EVOHs as those employed in the previouslydescribed resin composition with a thermoplastic resin (T1) areavailable as the modified EVOH (C) used in the dynamically crosslinkedresin composition. However, the preferably available modified EVOH (C)differs from those in the previously described resin composition withrespect to EVOH (A) used as a raw material thereof. This corresponds tothe differences in production method and applications of the resincompositions. Accordingly, the composition of the preferable modifiedEVOH (C) is also different because of the difference in EVOH (A) as araw material.

The EVOH (A), which is a raw material of the modified EVOH (C) used forthe dynamically crosslinked resin composition is a copolymer comprisingmainly ethylene units (—CH₂CH₂—) and vinyl alcohol units (—CH₂—CH(OH)—).Examples thereof include known ones such as those used for moldingapplications. It should be noted that the ethylene unit content in theEVOH (A) is preferably from 10 to 99 mol %, more preferably from 20 to75 mol %, still more preferably from 25 to 60 mol %, and particularlypreferably from 25 to 50 mol % from the viewpoints of the degrees ofbarrier properties to gas, organic liquid and the like or the degree ofmolding processability. The EVOH (A) is, as described later, typically asaponified product of an ethylene-fatty acid vinyl ester copolymer. Whenthe EVOH (A) is a saponified product of an ethylene-fatty acid vinylester copolymer, the degree of saponification of the fatty acid vinylester units is preferably not less than 50 mol %, more preferably notless than 90 mol %, still more preferably not less than 95 mol %, andparticularly preferably not less than 98 mol % from the viewpoint of thedegrees of barrier properties and heat stability of a resulting EVOH(A). The melt flow rate (measured under conditions including atemperature of 210° C. and a load of 2.16 kg by the method provided inASTM D1238) of the EVOH (A) is preferably from 0.1 to 100 g/10 minutes,more preferably from 0.5 to 50 g/10 minutes, and particularly preferablyfrom 1 to 20 g/10 minutes from the viewpoint of the degree of moldingprocessability. The limiting viscosity of the EVOH (A) in a mixedsolvent composed of 85% by weight of phenol and 15% by weight of waterat a temperature of 30° C. is preferably from 0.1 to 5 dl/g and morepreferably from 0.2 to 2 dl/g.

The EVOH (A) may have, in addition to ethylene units and vinyl alcoholunits, other constitutional units if in a small amount (preferably up to10 mol % based on the whole constitutional units). Examples of the“other constitutional units” include units derived from a-olefins suchas propylene, isobutylene, 4-methylpentene-1,1-hexene and 1-octene;carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate,vinyl versatate, vinyl pivalate, vinyl valerate, vinyl caprate and vinylbenzoate; unsaturated carboxylic acids and their derivatives (e.g.salts, esters, nitrites, amides and anhydrides) such as itaconic acid,methacrylic acid, acrylic acid and maleic anhydride; vinyl silanecompounds such as vinyl trimethoxysilane; unsaturated sulfonic acids andtheir salts; N-methylpyrrolidone; etc. The EVOH (A) may have afunctional group such as an alkylthio group at its terminal.

The method for producing the EVOH (A) is not particularly limited. Forexample, the EVOH (A) can be produced by preparing an ethylene-fattyacid vinyl ester copolymer according to a known method and thensaponifying the resulting copolymer. The ethylene-fatty acid vinyl estercan be obtained, for example, polymerizing monomers mainly comprisingethylene and fatty acid vinyl ester using a radical polymerizationinitiator such as benzoyl peroxide and azobisisobutyronitrile underpressure in an organic solvent such as methanol, t-butyl alcohol anddimethyl sulfoxide. Examples of available fatty acid vinyl ester includevinyl acetate, vinyl propionate, vinyl versatate, vinyl pivalate, vinylvalerate and vinyl caprate. Above all, vinyl acetate is preferable. Forthe saponification of the ethylene-fatty acid vinyl ester copolymer, anacid catalyst or an alkali catalyst may be employed.

The elastomer (J) having a functional group capable of reacting with acrosslinking agent (K) used in the dynamically crosslinked resincomposition is not particularly limited if it has in the molecule afunctional group capable of reacting with the crosslinking agent (K).For example, available are thermoplastic elastomers such asstyrene-based elastomer, olefin-based elastomer, synthetic rubber andnatural rubber.

Examples of the styrene-based elastomer include a block copolymercomprising mainly vinyl aromatic polymer blocks and conjugated dienepolymer blocks. Examples of the vinyl aromatic monomer used for theformation of the vinyl aromatic polymer blocks constituting the blockcopolymer include vinyl aromatic compounds such as styrene,α-methylstyrene, β-methylstyrene, o-, m-, p-methylstyrene,t-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene,monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene,methoxystyrene, vinylnaphthalene, vinylanthracene, indene andacetonaphthylene. The vinyl aromatic polymer blocks may have structuralunits comprised only of one kind of vinyl aromatic compound or,alternatively, the blocks may have structural units comprised of two ormore kinds of vinyl aromatic compounds. The vinyl aromatic polymerblocks are preferably comprised mainly of structural units derived fromstyrene.

The vinyl aromatic polymer block may optionally have, in addition tostructural units derived from vinyl aromatic compounds, structural unitsderived from other copolymerizable monomers, the proportion of which ispreferably not more than 30% by weight and more preferably not more than10% by weight based on the weight of the vinyl aromatic polymer block.

Examples of the other copolymerizable monomer units include units ofmonomers, e.g. 1-butene, pentene, hexene, butadiene, isoprene and methylvinyl ether.

Examples of the conjugate diene compound used for the formation of theconjugate diene polymer block in the block copolymer comprised mainly ofa vinyl aromatic polymer block and a conjugated diene polymer blockinclude isoprene, butadiene, hexadiene, 2,3-dimethyl-1,3-butadiene and1,3-pentadiene. The conjugated diene polymer block may be constituted ofeither one of these conjugated diene compounds or two or more of them.When the conjugated diene polymer block includes structural unitsderived from two or more kinds of conjugated diene compounds, thelinking mode thereof may be any of random, tapered, partially block andcombinations of two or more foregoing modes.

Above all, the conjugated diene polymer block is preferably apolyisoprene block made of monomer units comprised mainly of isopreneunits or a hydrogenated polyisoprene block resulting from hydrogenationof part or all of the unsaturated bonds of the polyisoprene block; apolybutadiene block made up of monomer units comprised mainly ofbutadiene units or a hydrogenated polybutadiene block resulting fromhydrogenation of part or all of the unsaturated bonds of thepolybutadiene block; or an isoprene/butadiene copolymer block made up ofmonomer units comprised mainly of isoprene units and butadiene units ora hydrogenated isoprene/butadiene copolymer block resulting fromhydrogenation of part or all of the unsaturated bonds of theisoprene/butadiene copolymer block.

In the above-mentioned polyisoprene block, which is capable of becominga constitutional block of the conjugated diene polymer block, the unitsderived from isoprene comprise, before hydrogenation of the block, atleast one group selected from the group consisting of a2-methyl-2-bunene-1,4-diyl group [—CH₂—C(CH₃)═CH—CH₂—; 1,4-bondingisoprene unit], an isopropenylethylene group [—CH(C(CH₃)═CH₂)—CH₂—;3,4-bonding isoprene unit] and a 1-methyl-1-vinylethylene group[—C(CH₃)(CH═CH₂)—CH₂—; 1,2-bonding isoprene group]. The proportion ofeach kind of units is not particularly limited.

In the above-mentioned polybutadiene block, which is capable of becominga constitutional block of the conjugated diene polymer block, beforehydrogenation of the block, it is preferable that from 70 to 20 mol %,especially from 65 to 40 mol %, of the butadiene units be2-butene-1,4-diyl groups (—CH₂—CH═CH—CH₂—; 1,4-bonding butadine unit)and from 30 to 80 mol %, especially from 35 to 60 mol % of the butadieneunits be vinylethylene groups [—CH(CH═CH₂)—CH₂—; 1,2-bonding butadineunit].

In the isoprene/butadiene copolymer block which can be theconstitutional block of the conjugated diene polymer block, the unitsderived from isoprene comprise, before hydrogenation, at least one kindof group selected from the group consisting of a2-methyl-2-butene-1,4-diyl group, an isopropenylethylene group and a1-methyl-1-vinylethylene group and the units derived from butadienecomprise a 2-butene-1,4-diyl group and/or a vinylethylene group. Theproportion of each unit is not particularly restricted. In theisoprene/butadiene copolymer block, the arrangement of the isopreneunits and the butadiene units may be any of a random mode, a block modeor a tapered block mode. The molar ratio of the isoprene units to thebutadiene units is preferably from 1:9 to 9:1, more preferably, from 3:7to 7:3.

In the block copolymer comprised mainly of vinyl aromatic polymer blocksand conjugated diene polymer blocks, it is preferable that part or allof the unsaturated double bonds in the conjugated diene polymer block beadded with hydrogen (henceforth referred to “hydrogenated”) from theviewpoint of achieving excellent heat resistance and weather resistanceof the resin composition. In this case, the hydrogenation rate of theconjugated diene polymer block is preferably 50 mol % or more, morepreferably 60 mol % or more and further preferably 80 mol % or more.

In the block copolymer, the molecular weights of the vinyl aromaticpolymer block and the conjugated diene polymer block are notparticularly limited. However, in a state before hydrogenation, thenumber average molecular weight of the vinyl aromatic polymer blockpreferably ranges from 2,500 to 75,000 and the number average molecularweight of the conjugated diene polymer block preferably ranges from10,000 to 150,000, from the viewpoints of mechanical properties andformability of the resin composition. It is noted that the numberaverage molecular weight of an elastomer (J) referred to in thisspecification indicates a value calculated from a standard polystyrenecalibration curve by means of gel permeation chromatography (GPC).

Although not particularly limited, the block copolymer can be producedby ion polymerization such as anion polymerization and cationpolymerization, single site polymerization, radical polymerization, andthe like.

In the case of anion polymerization, the block copolymer can bemanufactured by polymerizing a vinyl aromatic compound, a conjugateddiene compound, a monomer having a functional group reactable with acrosslinking agent and the like sequentially using an alkyl lithiumcompound or the like as a polymerization initiator in an inert organicsolvent such as n-hexane and cyclohexane to obtain a diblock or triblockcopolymer having a desired molecular structure and a desired molecularweight, and then stopping the polymerization by addition of an activehydrogen compound such as alcohol, carboxylic acid, water and the like.

Examples of olefin-based elastomer available as elastomer (J) in thepresent invention which has a functional group capable of reacting withthe crosslinking agent (K) include ethylene-propylene copolymer (EPR),ethylene-propylene-nonconjugated diene copolymer (EPDM) andethylene-α-olefin copolymer obtained by use of a metallocene-basedpolymerization catalyst.

Examples of synthetic rubber available as elastomer (J) includepolybutadiene, polyisoprene, polybutyl rubber, styrene-butadiene randomcopolymer, styrene-isoprene random copolymer, acrylonitrile-butadienecopolymer and polychloroprene. Moreover, natural rubber may be employedas elastomer (J). The double bonds contained in the above-mentionedsynthetic rubber or natural rubber may be hydrogenated.

Of those mentioned above, styrene-based elastomers are preferable andblock copolymer comprised mainly of vinyl aromatic polymer blocks andconjugated diene polymer blocks are more preferable as elastomer (J)because a resulting resin composition is excellent in flexibility and itis easy to introduce thereto a functional group capable of reacting withthe crosslinking agent (K).

Examples of the functional group contained in the elastomer (J) which iscapable of reacting with the crosslinking agent (K) include hydroxylgroup (e.g. primary hydroxyl group (—CH₂OH)), amino group, alkylaminogroup, epoxy group, ether group (e.g. alkoxyl group), carboxyl group,ester group (e.g. alkoxycarbonyl group and acyloxyl group), amide group(e.g. carbamoyl group, alkylcarbamoyl group and acylamino group), bromogroup, group with a dicarboxylic anhydride structure (e.g. maleicanhydride group), boronic acid group, boron-containing group capable ofbeing converted into a boronic acid group in the presence of water, anddouble bond (e.g. vinyl group). It is preferable that the functionalgroup capable of reacting with the crosslinking agent (K) be selectedappropriately depending on the combination with the crosslinking agent(K) so that the functional group demonstrates a higher reactivity to thecrosslinking agent (K) used than that demonstrated by a secondaryhydroxyl group (>CH—OH) the modified EVOH (C) has or a primary hydroxylgroup (—CH₂OH) derived from the structure of a monofunctional epoxycompound employed for modification.

The above-mentioned boronic acid group which the elastomer (J) cancontain in the present invention is a group represented by the followingformula (a):

Examples of the boron-containing group which is capable of beingconverted into a boronic acid group in the presence of water and whichthe elastomer (J) can contain (henceforth, the group being abbreviatedto a boron-containing group) include any boron-containing group capableof being converted into a boronic acid group when the elastomer (J) ishydrolized in water, a mixed liquid composed of water and an organicsolvent (e.g. toluene, xylene and acetone), or a mixed liquid composedof a 5% aqueous boronic acid solution and the aforementioned organicacid under conditions including a reaction time of from 10 minutes to 2hours and a reaction temperature of from room temperature to 150° C.Typical examples include a boronic acid ester group represented by thefollowing formula (b), a boronic anhydride group represented by thefollowing formula (c) and a group composed of a boronic acid saltrepresented by the following formula (d):

[In the formula, each of X and Y represents a hydrogen atom, analiphatic hydrocarbon group (e.g. a linear or branched alkyl or alkenylgroup having from 1 to 20 carbon atoms), an alicyclic hydrocarbon group(e.g. cycloalkyl group and cycloalkenyl group) or an aromatichydrocarbon group (e.g. phenyl group and biphenyl group), provided thatX and Y may be the same or may differ; X and Y may be combined together;a case where both X and Y are hydrogen atoms is excluded.]

[In the formula, each of R¹, R² and R³ represents a hydrogen atom,aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatichydrocarbon group the same as those represented by X and Y; R¹, R² andR³ may represent the same group or different groups; and M representsalkali metal or alkaline earth metal.] [Moreover, each of X, Y, R¹, R²and R³ may have another group such as a hydroxyl group, carboxyl groupand a halogen atom.]

Specific examples of the boronic acid ester group, boronic anhydridegroup and boronic acid base group represented by formula (b) to (d)include boronic ester groups such as boronic acid dimethyl ester group,boronic acid diethyl ester group, boronic acid dibutyl ester group,boronic acid dicyclohexyl group, boronic acid ethylene glycol estergroup, boronic acid propylene glycol ester group (boronic acid1,2-propanediol ester group and boronic acid 1,3-propanediol estergroup), boronic acid neopentyl ester group, boronic acid catechol estergroup, boronic acid glycerin ester group, boronic acid trimethylolethaneester group, boronic acid trimethylolethane ester group and boronic aciddiethanolamine ester group; boronic anhydride groups; a group of alkalimetal salt of boronic acid, and a group of alkaline earth metal salt ofboronic acid.

Of the foregoing functional groups, preferred are groups having adicarboxylic anhydride structure such as maleic anhydride group orboronic acid ester groups such as boronic acid ethylene glycol estergroup, boronic acid propylene glycol ester group, boronic acidtrimethylene glycol ester group, boronic acid 1,3-butanediol ester groupand boronic acid glycerin ester group because they are very reactive andthey can control the degree of crosslinking of elastomer (J) easily.

The average content of the functional groups is preferably not less than0.5 groups, more preferably from 1 to 50 groups and still morepreferably within a range of from 3 to 30 groups in one molecule ofelastomer (J). The method for introducing a functional group intoelastomer (J) is not particularly restricted. Examples of the methodinclude (1) a method which uses a copolymerizable monomer having afunctional group capable of reacting with a crosslinking agent (K), apolymerization initiator, a chain transfer agent, a terminator or thelike during the polymerization of the monomer for forming the elastomer(J); (2) a method in which a copolymerizable monomer which forms afunctional group capable of reacting with a crosslinking agent (K)through a reaction such as leaving, hydrolysis or the like of aprotective group, polymerization initiator, chain transfer agent,terminator or the like is used during the polymerization of monomers forforming elastomer (J) and, after the polymerization, a functional groupis formed; and (3) a method using a polymer reaction in which anoxidizing agent or the like is allowed to react on a polymer free offunctional group under melt condition to introduce a functional group.When the functional group which the elastomer (J) has is a group havinga dicarboxylic anhydride structure or a boronic acid ester group, thefunctional group can be introduced by the above-mentioned method (3)including an appropriate selection of a compound (oxidizing agent)having a structure corresponding to the functional group.

The functional group may be introduced to any position in the elastomer(J), e.g. a position in a main chain, short branch chain or terminal ofa molecular chain.

The crosslinking agent (K) for use in the present invention is notparticularly restricted if it is a compound with two or morefunctionalities which is capable of reacting with a functional group ofthe elastomer (J) and which is liquid or solid but does not decomposethe modified EVOH (C) at a melt kneading temperature in the productionof a resin composition.

For example, when the functional group of the elastomer (J) is a grouphaving a dicarboxylic anhydride structure, diamines such as1,9-nonanediamine and 2-methyl-1,8-octanediamine and diols such as1,6-hexanediol and 1,9-nonanediol are suitable employed as thecrosslinking agent (K).

On the other hand, when the functional group of the elastomer (J) is aboronic acid ester group, compounds having four or more hydroxyl groupsin one molecule, such as pentaerythritol, inositol, glucose, heptose andlactose, are suitably employed as the crosslinking agent (K).

The blending proportions of the above-mentioned components (C), (J) and(K) in the dynamically crosslinked resin composition of the presentinvention are 100 parts by mass of the modified EVOH (C), from 5 to 900parts by mass, preferably from 40 to 800 parts by mass, based on 100parts by mass of the modified EVOH (C), of the elastomer (J) having afunctional group capable of reacting with the crosslinking agent (K),and from 0.05 to 30 parts by mass, preferably from 0.2 to 20 parts bymass, based on 100 parts by mass of the elastomer (J), of thecrosslinking agent (K).

When the compounding amount of the elastomer (J) based on 100 parts bymass of the modified EVOH (C) is less than 5 parts by mass, a resultingresin composition should have a poor flexibility. On the other hand,when over 900 parts by mass, a resulting resin composition should havepoor gas barrier properties.

When the compounding amount of the elastomer (K) based on 100 parts bymass of the elastomer (J) is less than 0.05 part by mass, a resultingresin composition should have poor gas barrier properties. When over 30parts by mass, a molded article comprised of the composition should havea poor surface appearance.

The dynamically crosslinked resin composition of the present inventioncan be prepared by dynamically crosslinking the above-mentionedcomponents (C), (J) and (K) under melt conditions. This process includesmelt kneading the modified EVOH (C) and the elastomer (J) to form fineand homogeneous dispersion and further forming crosslinkages betweenfunctional groups of the elastomer (J) by action of the crosslinkingagent (K).

For the melt kneading, any melt kneading device capable of mixing thecomponents homogeneously may be employed. Examples of such a meltkneading device include a single screw extruder, a twin screw extruder,a kneader and a Banbury mixer. Above all, a twin screw extruder, whichgenerates great shear force during kneading and can be drivencontinuously, is preferably employed.

The dynamically crosslinked resin composition of the present inventioncan be produced concretely through a process described below. That is,the modified EVOH (C) and the elastomer (J) are mixed and introducedinto a hopper of an extruder. Some part of the modified EVOH (C) may beadded at the middle of the extruder. The crosslinking agent (K) may beadded either at the beginning together with the modified EVOH (C) andthe elastomer (J) or at the middle of the extruder. Moreover, thecomponents may be melt kneaded stepwise by use of two or more extruders.

The melt kneading temperature is preferably from about 160 to about 280°C., and more preferably from 200° C. to 240° C. The melt kneading timeis preferably from 30 seconds to 5 minutes.

The resin composition obtained in the manner described above has astructure such that elastomer (J) crosslinked by crosslinking agent (K)is dispersed in a matrix of modified EVOH (C). The diameter of thedispersion particles of the crosslinked elastomer (J) is preferably from0.1 to 30 μm more preferably from 0.1 to 20 μm.

Moreover, the dynamically crosslinked resin composition of the presentinvention may contain paraffin oil for having an enhanced flexibility.In general, oils used as process oil or the like are mixtures ofcomponents having aromatic rings such as a benzene ring and a naphthenering and paraffin components (chain hydrocarbon) and the like. Oil suchthat the number of the carbon atoms constituting paraffin chainsaccounts for at least 50% by mass of all carbon atoms in the oil iscalled “paraffin oil”. As the paraffin oil used in the dynamicallycrosslinked resin composition of the present invention, any oil which iscalled “paraffin oil” can be used. Oils such that the content of thecomponent having aromatic rings is up to 5% by mass are preferablyemployed.

The compounding amount of the paraffin oil is preferably up to 200 partsby mass based on 100 parts by mass of the elastomer (J). The kinematicviscosity of the paraffin oil at 40° C. is preferably from 20×10⁻⁶ to800×10⁻⁶ m²/sec, more preferably from 50×10⁻⁶ to 600×10⁶ m²/sec. Thepour point is preferably from −40 to 0° C., more from −30 to 0° C. Theflash point is preferably from 200 to 400° C., more from 250 to 350° C.In the production of the resin composition, the paraffin oil may be meltkneaded after the elastomer (J) is impregnated therewith or may be addedfrom the middle of melt kneading. Moreover, both the impregnation andthe midway addition may be used together.

The dynamically crosslinked resin composition of the present inventionmay contain, in addition to the above-mentioned components, otherpolymers as required unless the effect of the present invention issubstantially adversely affected. Examples of the polymers which can beincorporated include resins such as polyethylene, polypropylene,polyamide and polyester.

Moreover, the dynamically crosslinked resin composition of the presentinvention may, as required, contain inorganic filler, dye and pigment,etc. for the purposes of reinforcement, extending, coloring, and thelike. Examples of inorganic filler, dye and pigment include calciumcarbonate, talc, clay, synthetic silicon, titanium oxide, carbon blackand barium sulfate. The amount of the inorganic filler, dye and pigmentincorporated is preferably within a range such that the barrierproperties of the resin composition to gases and organic liquids are notdamaged. In general, the amount is preferably up to 50 parts by massbased on 100 parts by mass of the modified EVOH (C) and elastomer (J) intotal.

The dynamic crosslinked resin composition of the present invention maycontain, in addition to the above-mentioned components, one or two ormore other components such as crosslinking aid, lubricant, lightstabilizer, flame retardant, antistatic agent, silicone oil,anti-blocking agent, ultraviolet absorber, antioxidant, mold lubricant,foaming agent and perfume, as required.

The applications of the resin composition of the present invention willbe described below. In the description on the applications, the resincomposition encompasses both embodiments of a resin compositioncomprising a modified EVOH (C) and a thermoplastic resin (T1) and aresin composition resulting from dynamic crosslinking treatment.However, unless otherwise stated, the resin composition is suitable forthe applications of the resin composition comprising the modified EVOH(C) and the thermoplastic resin (T1).

The resin composition of the present invention is molded into variousmolded articles such as films, sheets, containers, pipes, hoses andfibers suitably by melt molding. These molded articles may be crushedand molded again for the purpose of recycling. In addition, films,sheets, fibers and the like may be drawn uniaxially or biaxially. As amethod of melt molding, available are extrusion molding, melt spinning,injection molding, injection blow molding and the like. The meltingtemperature of the resin composition may vary depending upon the meltingpoint or the like of the thermoplastic resin (T1) and the modified EVOH(C), but it is preferably about 120-270° C.

The resin composition of the present invention is preferably used in theform of an extruded article. The method for producing the extrudedarticle is not limited particularly, but preferable examples thereofinclude film extrusion cast molding, sheet extrusion cast molding, pipeextrusion molding, hose extrusion molding, profile extrusion molding,extrusion blow molding and inflation extrusion molding. Extrusion moldedarticles obtained by such molding methods can be subjected to secondaryprocessing such as uniaxial or biaxial stretching and thermoforming.

As described previously, conventional EVOHs are superior in transparencyand gas barrier properties, but they have drawbacks of being poor instretchability, flexibility and flexing resistance. On this account EVOHis often required to be laminated with other resin or resins when theEVOH is used for an application where the impact resistance is required,such as a bottle, and for an application where the flexibility and theflexing resistance are required, such as a film and a flexible packagingcontainer. However, the resin composition of the present invention canbe used in the form of a monolayer molded article even in an applicationwhere the impact resistance and/or the flexing resistance is requiredbecause it shows superior performances with respect to barrierproperties, transparency, stretchability, flexibility and flexingresistance. From a viewpoint of such expansion of applications, thepresent invention is of great significance.

From a viewpoint of effective utilization of the resin composition ofthe present invention which is superior in barrier properties, impactresistance, flexibility and flexing resistance, a film, an extrusionblow molded article (suitably, a bottle, etc.), a flexible packagingcontainer (suitably, a flexible tube, a flexible pouch, etc.), a pipe, ahose and a profile extruded article are desirable as a monolayer moldedarticle of the resin composition. In addition, a oriented film isparticularly preferable as the above-mentioned film from a viewpointwhere the characteristic of the resin composition of the presentinvention of being superior in stretchability can be used. Above all,preferred is a oriented film stretched at least uniaxially two times ormore. Furthermore, it is preferable to use the oriented film as a heatshrinkable film.

Of these monolayer molded articles, for applications in which a highdegree of barrier property is required even the wall is thin or forapplications in which transparency is required, it is preferable to usean EVOH (F) free of the aforementioned structural unit (I) as thethermoplastic resin (T1) to be incorporated to the modified EVOH (C).Examples of such applications include oriented films, thermoformablefilms, heat shrinkable films and flexible packaging containers. On theother hand, in molded articles which are not required for transparency,thick-walled molded articles, molded articles which are not required forhigh barrier properties, etc., it is preferable to use otherthermoplastic resin, especially polyolefin (G) as the thermoplasticresin (T1) incorporated to modified EVOH (C). Examples of suchapplications include thick-walled injection molded articles,complex-shaped injection molded articles, monolayer pipes or hoses, andmonolayer extrusion blow molded containers. Examples of the thick-walledinjection molded articles include caps for food packaging containers,and fillers and joints of fuel tanks. Examples of the complex-shapedinjection molded articles include pouring openings with a pull ring.Moreover, in the case where the resin composition is one recycled frommolded articles, it is preferable to use a polyolefin (G) asthermoplastic resin (T1). This is because use of modified EVOH (C)improves the recyclability.

For improvement in barrier property and shape retainability at hightemperature and high humidity and for improvement in shrinkability whenused in a heat shrinkable film application or the like, the resincomposition of the present invention may be provided with a crosslinkingstructure to an extent where the effect of the present invention is notadversely affected. There are no particular limitations for the methodfor forming the crosslinking structure and a preferable method is onecomprising irradiation with energy rays. Examples of the energy raysinclude ionizing radiation such as ultraviolet rays, electron beam,X-rays, α-rays and γ-rays. Electron beam is preferred.

An example of the method of irradiation with electron beam include amethod in which after a primary processing by extrusion molding, aresulting molded article is introduced to an electron beam irradiationapparatus and then the article is irradiated with electron beam. Theamount of the electron beam applied is not limited particularly, but itis preferably within the range of 1-40 Mrad. If the amount of theelectron beam applied is less than 1 Mrad, crosslinking will become hardto proceed. On the other hand, if the amount of the electron beamapplied exceeds 40 Mrad, deterioration of the molded article becomeseasy to proceed. It is more preferable that the amount of the electronbeam be within the range of 2-30 Mrad.

For a molded article which requires to be subjected to secondary formingsuch as stretching (uniaxially or biaxially) and thermoforming after theprimary molding, it is preferable to perform the electron beamirradiation between the primary molding and the secondary forming. Inthe above-mentioned crosslink treatment, as an electron beam which canbe used, those with an energy of 150-10000 KeV released from variouskinds of electron beam accelerators such as Cockcroft-Watson type, Vander Graaff type, resonance transformer type, insulated core transformertype, linear accelerator, dynamitron type and high frequency cyclotronare used, but the electron beam used is not limited thereto.

In addition, it is desirable to use a resin composition containing acrosslinking aid when performing the above-mentioned crosslinktreatment. Preferable examples of the crosslinking aid include allylcompounds and (meth)acrylic compounds having at least two functionalgroups. Specific examples include triaryl cyanurate (TAC), triarylisocyanurate (TAIC), pentaerythritol tetramethacrylate (PETMA),glutaraldehyde (GA), ethylene glycol dimethacrylate (EGDMA), diallylmaleate (DAM), dipropagyl maleate (DPM), dipropagyl monoallylcyanurate(DPMAC), trimethylolpropane triacrylate (TMPTAT), tetraethylene glycoldiacrylate (TEGDA), 1,6 hexaglycol diacrylate, tetramethylol methanetetraacrylate, dipropagyl succinate, diallyl fumarate and diallyphthalate. Among these, triallyl cyanate and triaryl isocyanate areparticularly desirable.

The resin composition of the present invention is offered for practicaluse also as a single-layer molded article as described above. However,it is also desirable to use it in the form of a multilayer structure inwhich the resin composition and a thermoplastic resin (T2) arelaminated. When the resin composition of the present invention, which isoften used as a barrier material, is designated as Barrier, an adhesiveresin is designated as Ad, a resin other than said barrier material isdesignated as R and a scrap recovery layer is designated as Reg, thelayer constitution of the multilayer structure may be, but not limitedto, Barrier/R, R/Barrier/R, Barrier/Ad/R, Reg/Barrier/R,R/Ad/Barrier/Ad/R and R/Reg/Ad/Barrier/Ad/Reg/R and the like. Inaddition, when layers of thermoplastic resin (T2) are disposed on bothsides of a layer of the resin composition of the present invention, thelayers disposed may be of the same kind or alternatively of differentkinds. Furthermore, a recovered resin may be blended in the resin otherthan the resin composition of the present invention. In the multilayerstructures, each layer may be single-layered, or, as the case may be,multilayer.

The method of producing the multilayer structure as above is notspecifically defined. For example, employable are a method ofmelt-extruding, onto a molding (e.g. film or sheet) of the resincomposition of the present invention, the thermoplastic resin (T2); amethod of melt-extruding the resin composition of the present inventiononto a substrate of the thermoplastic resin (T2); a method ofcoextruding the resin composition of the present invention along withthe thermoplastic resin (T2); and a method of laminating a moldingobtained from the resin composition of the present invention and a filmor sheet of the thermoplastic resin (T2) via a known adhesive of, forexample, organotitanium compounds, isocyanate compounds and polyestercompounds therebetween. Of those, preferred is the method of coextrudingthe resin composition of the present invention along with thethermoplastic resin (T2).

As the thermoplastic resin (T2) to be laminated with the resincomposition of the present invention, preferred is at least one selectedresin from the group consisting of polyolefin, polyamide, polyester,polystyrene, polyvinylidene chloride, polyvinyl chloride,polyacrylonitrile, thermoplastic polyurethane and polycarbonate. Amongthese, polyolefin, polyamide, polystyrene, polyester and thermoplasticpolyurethane are preferably used.

The polyolefin used as the thermoplastic resin (T2) in the presentinvention is not specifically defined and may, for example, be ahomopolymer or copolymer of an olefin such as linear low densitypolyethylene, low density polyethylene, medium density polyethylene,high density polyethylene, ethylene-vinyl acetate copolymer,ethylene-propylene copolymer, polypropylene, propylene-α-olefincopolymer (α-olefin having 4-20 carbon atoms), polybutene, polypentene.Examples of the copolymerizing components other than these α-olefinsinclude diolefins, vinyl compounds such as N-vinylcarbazole, vinylchloride, vinylidene chloride, styrene, acrylonitrile and vinyl ether;unsaturated carboxylic acids, such as maleic acid, acrylic acid,methacrylic acid, ethacrylic acid, fumaric acid and itaconic acid, theiresters and anhydrides; and components resulting from addition of ahydroxyl group or an epoxy group to the foregoing components. Forexample, various copolymers such as copolymers of a graftable monomerand a polyolefin and ionomer resins, which are reaction products ofα-olefin/α,β-unsaturated carboxylic acid copolymers with ionic metalcompounds, may be used. As the polyolefin, chlorinated polyethylene,chlorinated polypropylene and the like may also be used. Thesepolyolefin resins may be used alone or may be used in combination of twoor more. Among the examples shown above, polypropylene, polyethylene,ethylene-propylene copolymer and ethylene-vinyl acetate copolymer areused particularly preferably.

Examples of the polyamide used as the thermoplastic resin (T2) in thepresent invention include polycapramide (nylon-6), poly-ω-aminoheptanoicacid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecamide(nylon-11), polylauryl lactam (nylon-12), polyethylene adipamide(nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethyleneadipamide (nylon-6,6), polyhexamethylene sebacamide (nylon-6,10),polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide(nylon-8,6), polydecamethylene adipamide (nylon-10,6),polydodecamethylene sebacamide (nylon-12,10) or caprolactam/lauryllactam copolymer (nylon-6/12), caprolactam/ω-aminononanoic acidcopolymer (nylon-6/9), caprolactam/hexamethylene adipamide copolymer(nylon-6/6,6), lauryl lactam/hexamethylene adipamide copolymer(nylon-12/6,6), hexamethylene adipamide/hexamethylene sebacamidecopolymer (nylon-6,6/6,10), ethylene adipamide/hexamethylene adipamidecopolymer (nylon-2,6/6,6), caprolactam/hexamethyleneadipamide/hexamethylene sebacamide copolymer (nylon-6/6,6/6,10),polyhexamethylene isophthalamide, polyhexamethylene terephthalamide andhexamethylene isophthalamide/terephthalamide copolymer. These polyamidemay be used alone or alternatively may be used in combination of two ormore. Among these polyamides, preferred are polyamides containing acaproamide component, for example, nylon-6, nylon-6,12, nylon-6/12,nylon-6/6,6.

The polyester used as the thermoplastic resin (T2) in the presentinvention is not specifically defined. Suitable examples thereof includepoly(ethylene terephthalate) poly(butylene terephthalate), poly(ethyleneterephthalate/isophthalate) and poly(ethyleneglycol/cyclohexanedimethanol/terephthalate). Among these, particularlypreferred is poly(ethylene terephthalate). In addition, as thepolyester, polyesters containing as a copolymerizing component diols,such as ethylene glycol, butylene glycol, cyclohexanedimethanol,neopentyl glycol and pentane diol, and dicarboxylic acids, such asisophthalic acid, benzophenone dicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylmethane dicarboxylic acid,propylenebis(phenylcarboxylic acid), diphenyl oxide dicarboxylic acid,oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,pimelic acid, suberic acid, azelaic acid, sebacic acid anddiethylsuccinic acid, may also be employed.

In addition, it is also preferable to use an elastomer as thethermoplastic resin (T2) to be laminated with the resin composition ofthe present invention. The elastomer for use in the present invention isnot specifically defined. Suitable examples thereof includepolyurethane-based elastomers, polystyrene-based elastomers,polyamide-based elastomers, polyester elastomers, polyolefin-basedelastomers, elastomers comprising copolymers of vinyl aromatic compoundswith conjugated diene compounds.

The polyurethane-based elastomer used as the thermoplastic resin (T2) inthe present invention may usually be, but is not limited to, those madeup of two or three constituents such as a high molecular diol andorganic diisocyanate and/or low molecular diol. Specific examples ofeach component are as follows.

The high molecular diol is a diol which is a high molecular compoundresulting from polycondensation, addition polymerization (for example,ring opening polymerization) or polyaddition, typical examples of whichinclude polyester diol, polyether diol, polycarbonate diol or theircocondensate (for example, polyester and ether diol). These may be usedalone or alternatively may be used in combination of two or more.

As the polyester diol, polyester diols obtained from an aliphatic diolsuch as ethylene glycol, propylene glycol and 1,5-pentane diol or amixture there of and an aliphatic or aromatic dicarboxylic acids such asglutaric acid, adipic acid and terephthalic acid or a mixture thereofmay be used. Alternatively, polylactone diol such as polycaprolactoneglycol, polypropiolactone glycol and polyvalerolactone glycol may beused suitably. As the polyether diol, polyalkylene ether diol such aspolyethylene ether glycol, polytetramethylene ether glycol andpolyhexamethylene ether glycol may be used suitably. Furthermore, as thepolycarbonate diol, a polycarbonate diol resulting from condensationpolymerization by applying diphenyl carbonate or phosgene to analiphatic diol having 2-12 carbon atoms such as 1,4-butanediol,1,5-pentanediol, 1,6-hexane diol, 1,8-octanediol and 1,10-decane diol ora mixture thereof may be used suitably.

It is desirable that the average molecular weight of the high moleculediol be within the range of 500-3000, more preferably within the rangeof 500-2500. If the average molecular weight is too small, thecompatibility with an organic diisocyanate will be too good and theelasticity of a resulting polyurethane will be poor. On the other hand,if the average molecular weight is too large, the compatibility with anorganic diisocyanate will be bad and blending in a polymerizationprocess will be unsuccessful, producing gel-like blocks or failing toform stable polyurethane.

Examples of the second raw material, the low molecular diol, include lowmolecular diols with a molecular weight of less than 500 e.g. aliphatic,alicyclic or aromatic diols such as ethylene glycol, propylene glycol,1,4-butanediol, 1,5-pentane diol, 3-methylpentane glycol, 1,6-hexanediol and 1,4-bishydroxyethylbenzene. These may be used alone oralternatively may be used in combination of two or more.

Examples of the organic diisocyanate include aromatic, alicyclic oraliphatic diisocyanates such as 4,4-diphenylmethane diisocyanate,tolylene diisocyanate, 1,3- or 1,4-bis(isocyanatemethyl)benzene, 1,3- or1,4-bis(isocyanatemethyl)cyclohexane, 4,4′-dicyclohexylmethanediisocyanate and isophorone diisocyanate. These organic diisocyanatesmay be used alone or alternatively may be used in combination of two ormore.

The nitrogen content of the polyurethane-based elastomer used as thethermoplastic resin (T2) in the present invention is determined throughappropriate selection of the proportions of the high molecular diol, lowmolecular and organic diisocyanate. However, it is preferably within therange of 1-7% in practical use. Moreover, when a thermoplasticpolyurethane is used, an appropriate catalyst which promotes thereaction between the organic diisocyanate and the diol may be employedas required. In addition, various additives such as coloring agents,fillers, oxidation inhibitors and ultraviolet absorbers or lubricantsmay also be added for each purpose.

The polyolefin-based elastomer used as the thermoplastic resin (T2) inthe present invention may suitably be, but are not limited specificallyto, ethylene-propylene copolymer elastomer (EPR). The ethylene-propylenecopolymer may be, but is not limited specifically to, random copolymersand block copolymers of ethylene and propylene. As for the content ofeach constituent, in order for the copolymer to have a sufficientflexibility, it is preferable that one constituent exist in an amount atleast 10% by weight or more, more preferably 20% by weight or more.

The elastomer comprising a copolymer of a vinyl aromatic compound and aconjugated diene compound used as the thermoplastic resin (T2) in thepresent invention is not limited specifically. Examples of such a vinylaromatic compound include styrenes such as styrene, α-methylstyrene,2-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene,4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene,4-(phenylbutyl)styrene, 2,4,6-trimethylstyrene, monofluorostyrene,difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene andt-butoxystyrene; aromatic compounds containing a vinyl group such as1-vinylnaphthalene and 2-vinylnaphthalene; aromatic compounds containinga vinylene group such as indene and acenaphthylene. The vinyl aromaticmonomer unit may be of one kind or may be of two or more kinds. However,it is preferably a unit derived from styrene.

In addition, a conjugated diene compound used for copolymer comprisingof vinyl aromatic compound and conjugated diene compound is not limitedparticularly. Examples of the conjugated diene compound includebutadiene, isoprene, 2,3-dimethylbutadiene, pentadiene and hexadiene.The conjugated diene compound may be partially or completelyhydrogenated. Examples of the partially hydrogenated copolymer of avinyl aromatic compound and a conjugated diene compound includehydrogenation products of styrene-ethylene•butylene-styrene triblockcopolymers (SEBS), styrene-ethylene•propylene-styrene triblockcopolymers (SEPS) and styrene-conjugated diene copolymers.

Among the elastomers shown above as examples, use of thepolyurethane-based elastomer is preferable because it is superior ininterlayer adhesiveness between a layer of the elastomer and a layer ofthe resin composition of the present invention, particularly, a resincomposition comprising the modified EVOH (C) and an EVOH (F).

As described previously, a multilayer structure in which the resincomposition of the present invention and the thermoplastic resin (T2)are laminated is produced suitably by coextrusion of the resincomposition and the thermoplastic resin (T2). Depending upon the type ofthe resin which is laminated to the resin composition, the resincomposition and the thermoplastic resin (T2) may be laminated via anadhesive resin. The adhesive resin used in this occasion is preferablyan adhesive resin comprising a carboxylic acid-modified polyolefin. Thecarboxylic acid-modified polyolefin is a modified olefinic polymerhaving carboxyl groups that may be prepared by chemically bonding anethylenic unsaturated carboxylic acid or its anhydride to an olefinicpolymer, for example, through addition reaction or grafting reaction.The olefinic polymer includes, for example, polyolefins such aspolyethylenes (produced in low-pressure, middle-pressure orhigh-pressure process), linear low density polyethylenes, polypropylenesand polybutenes; copolymers of olefins with comonomers capable ofcopolymerizing with olefins (e.g. vinyl esters and unsaturatedcarboxylates), such as ethylene-vinyl acetate copolymers andethylene-ethyl acrylate copolymers. Of those, preferred are linear lowdensity polyethylenes, ethylene-vinyl acetate copolymers (having a vinylacetate content of from 5 to 55% by weight), and ethylene-ethylacrylatecopolymers (having an ethyl acrylate content of from 8 to 35% byweight); and more preferred are linear low density polyethylenes andethylene-vinyl acetate copolymers. The ethylenic unsaturated carboxylicacid and its anhydride include, for example, ethylenic unsaturatedmonocarboxylic acids and their esters, ethylenic unsaturateddicarboxylic acids and their mono- or di-esters and anhydrides. Ofthose, preferred are ethylenic unsaturated dicarboxylic acid anhydrides.Concretely, they include maleic acid, fumaric acid, itaconic acid,maleic anhydride, itaconic anhydride, monomethyl maleate, monoethylmaleate, diethyl maleate and monomethyl fumarate. Above all, mostpreferred is maleic anhydride.

The amount of the ethylenic unsaturated carboxylic acid or its anhydrideto be added to or grafted on the olefinic polymer (that is, the degreeof modification) is between 0.0001 and 15% by weight of the olefinicpolymer, preferably between 0.001 and 10% by weight. Addition reactionor grafting reaction of the ethylenic unsaturated carboxylic acid or itsanhydride to the olefinic polymer is effected, for example, throughradical polymerization in a solvent (e.g. xylene) in the presence of acatalyst (e.g. peroxide). The melt flow rate (MFR) of the thus-preparedcarboxylic acid-modified polyolefin, when measured at 190° C. and undera load of 2160 g, is preferably 0.2-30 g/10 min, more preferably 0.5-10g/10 min. These adhesive resins may be used alone or alternatively maybe used in combination of two or more.

When the resin composition of the present invention is coextrusionmolded with the thermoplastic resin (T2), there are merits describedbelow in comparison with a normal EVOH. One of the merits is thatbecause the resin composition of the present invention has superiorbarrier properties, transparency, stretchability, flexibility andflexing resistance, it is possible to impart such superior physicalproperties also to multilayer molded articles containing a layercomprising the resin composition.

Another merit is one derived from the fact that the modified EVOH (C)used in the present invention has a lower melting point in comparisonwith normal EVOHs. The melting point of the modified EVOH (C) may varydepending upon the content of the above-mentioned structural unit (I),but the melting point of the modified EVOH (C) having the structuralunit (I) is lower than those of normal unmodified EVOHs. This merit isnoticeable in the case of a resin composition comprising the modifiedEVOH (C) and a polyolefin (G).

EVOH is often used in the form of a laminate with polyolefin. Such alaminate is often produced by coextrusion molding. However, because anEVOH having an ethylene content of 5-55 mol % is generally a resinhaving a melting point higher than those of polyolefin and the like,there used to be a necessity, in an occasion where the EVOH and apolyolefin is melt molded by coextrusion molding, of carrying out themolding at a temperature higher than the melting point of the EVOH. Inother words, as for the molding temperature of polyolefin, coextrusionmolding thereof used to be carried out at a molding temperature whichwas not always optimum.

However, use of the resin composition of the present invention has madeit possible to carry out coextrusion molding at a molding temperaturenear the optimum molding temperature of polyolefin. Because the range ofthe molding temperature employed in coextrusion molding has beenwidened, it has become easier to adjust a viscosity matching of apolyolefin and the resin composition of the present invention and it hasbecome possible to obtain coextrusion molded articles at more favorableoperating conditions. From such viewpoints, the present invention is ofhigh significance.

The method of coextruding the resin composition of the present inventionand the thermoplastic resin (T2) is not limited specifically. Suitableexamples thereof include the multimanifold method, the feedblock methodand the multislot die method. By such molding methods, a multilayerfilm, a multilayer sheet, a multilayer pipe, a multilayer hose, amultilayer profile molded article and the like are produced. Inaddition, the coextrusion inflation molding method, the coextrusion blowmolding method and the like can provide a multilayer film and amultilayer bottle.

The thus-obtained coextruded multilayer structures can be secondarilyfabricated into various shaped articles (e.g. films, sheets, tubes orbottles), which include the following:

-   (1) Multilayer co-stretched sheets or films, which are produced by    uniaxially or biaxially stretching multilayer structures (e.g.    sheets or films), or biaxially stretching them, and thereafter    thermally treating them.-   (2) Multilayer rolled sheets or films, which are produced by rolling    multilayer structures (e.g. sheets or films).-   (3) Multilayer tray or cup containers, which are produced through    thermoforming process such as vacuum forming, pressure forming and    vacuum-pressure forming of multilayer structures (e.g. sheets or    films).-   (4) Multilayer bottle or cup containers, which are produced through    stretch blow molding of multilayer structures (e.g. pipes).

The method for secondary fabrication of the multilayer structures is notlimited to the above, and any other known fabricating methods (e.g. blowmolding) could be employed.

Because the resin composition of the present invention is superior inbarrier properties, transparency, stretchability, flexibility andflexing resistance, a multilayer structure containing a layer comprisingthe resin composition of the present invention can be employed forvarious applications. For example, it is desirably employed for aflexible film, a flexible packaging material, a thermoformed container,a blow molded article (e.g. a multilayer coextrusion blow moldedcontainer and a multilayer coinjection blow molded container), a heatshrinkable film (e.g. a skin packaging film), a hose or a balloon. Aboveall, preferable examples of the applications in which the effect of theflexing resistance can be shown sufficiently include a flexiblepackaging material (e.g. a flexible pouch and a tube) and a flexiblefilm.

Of these multilayer moldings, for applications in which a high degree ofbarrier property is required even if the resin composition layer is thinor for applications in which transparency is required, it is preferableto use unmodified EVOH (F) as the thermoplastic resin (T1) to beincorporated to modified EVOH (C). Examples of such applications includeoriented films, thermoforming films, thermoforming sheets,heat-shrinkable films, flexible packaging containers, blow moldedcontainers, pipes, hoses and balloons. Above all, in applications wheresecondary processability is required such as oriented films,thermoforming films, thermoforming sheets, heat-shrinkable films andblow molded containers, the difference in ethylene content betweenmodified EVOH (C) and EVOH (F) is preferably from 2 to 30 mol %. Inparticular, it is preferable that the ethylene content of modified EVOH(C) be greater than that of EVOH (F) because an excellent secondaryprocessability is achieved while characteristics of the EVOH (F) havinggood gas barrier properties are maintained.

On the other hand, in molded articles which are not required fortransparency, thick-walled molded articles, molded articles which arenot required for high barrier properties, etc., it is preferable to useother thermoplastic resin, especially polyolefin (G) as thethermoplastic resin (T1) incorporated to modified EVOH (C). Examples ofsuch applications include two-color molded articles, insert moldedarticles, coinjection molded articles, thick-walled multilayer pipes orhoses, and thick-walled multilayer blow molded containers.

In addition, a multilayer structure in which the resin composition ofthe present invention and the thermoplastic resin (T2) are laminated ispreferably employed as a wallpaper or a decoration board. Because EVOHhas a superior antifouling property and superior barrier properties to aplasticizer, a multilayer structure containing an EVOH layer is suitablyemployed as a wallpaper. However, a wallpaper is often handled in theform of a roll during its transportation or its storage in a warehouse.When the transportation is repeated many times, the increase infrequency of bending of a wallpaper may render its appearance poorthrough formation of wrinkles in the EVOH layer or, when the wrinklesare severe, may cause whitening. However, the resin composition of thepresent invention is very suitable for such applications because it hassuperior flexibility and flexing resistance while holding a superiorbarrier property to a plasticizer. For this application, it is desirableto use the EVOH (F) as the thermoplastic resin (T1) to be incorporatedto the modified EVOH (C).

Moreover, it is also preferable that a flexible film comprising theresin composition of the present invention be laminated with artificialleather or the like to be employed as a book jacket because the flexiblefilm is superior in the antifouling property, flexibility and flexingresistance as described above. It is also preferable to use it for acover of a book, a cover of a notebook or the like, etc. Also for thisapplication, it is desirable to use the EVOH (F) as the thermoplasticresin (T1) to be incorporated to the modified EVOH (C).

Moreover, when a multilayer structure having a layer of the resincomposition of the present invention and a layer of the thermoplasticresin (T2) is used in the form of a multilayer pipe, a multilayer pipesuperior in crack resistance can be obtained. In a preferred embodiment,the multilayer pipe is a multilayer pipe comprising a laminate having anintermediate layer of the resin composition of the present invention andan inner and outer layers of a polyolefin. It is particularly preferablethat the multilayer pipe be employed as a fuel pipe or a pipe for warmwater circulation. The fuel pipe is available as a fuel pipe for carsand a so-called fuel line for transporting fuel from oil fields. Thesemultilayer pipes are usually used while being joined together throughconnectors. When the multilayer pipes are joined together throughconnectors, in many cases, the pipes are expanded slowly first throughtheir several expansions of the diameters of their ends by means of aspecial expansion jig.

In such a process, a conventional multilayer pipe containing a normalEVOH as a middle layer used to be suffered from cracking in the EVOH inthe portion where the diameter of the multilayer pipe has been expanded.In particular, during the task done in an environment where the outdoortemperature is very low, for example, in an area where floor heatingpipes are laid, large cracks are sometimes formed in a layer of EVOH.The cracks may reduce the oxygen barrier property in the connectedportions of the multilayer pipes. However, because the resin compositionof the present invention is superior in flexibility, it is possible toinhibit effectively the formation of cracks in a layer of the resincomposition even during such a step of connecting pipes.

On the other hand, the multilayer pipe is also used as a fuel pipesuitably. In this case, the fuel pipe is employed as a fuel pipe of carsvery suitably. It is used as a fuel pipe for supplying fuel from a fueltank to an engine. In such an embodiment, cracks are easily formed inthe barrier layer because a load caused by vibration of an engine orvibration occurring during the running of a car is applied continuouslyto the fuel pipe. However, because the resin composition of the presentinvention is superior in flexibility, it is possible to inhibiteffectively the formation of cracks in a layer of the resin compositioneven when the pipe is used as a fuel pipe.

From the viewpoints described above, it is very advantageous to employ amultilayer structure containing a layer of the resin composition of thepresent invention in the form of a multilayer pipe. In particular, it ispreferable to use the multilayer pipe as a fuel pipe or a pipe for warmwater circulation. For this application, it is desirable to use the EVOH(F) as the thermoplastic resin (T1) to be incorporated to the modifiedEVOH (C).

In addition, it is also preferable to use the multilayer structurecontaining a layer of the resin composition of the present invention asa multilayer hose. Because a hose is softer than a pipe, the multilayerhose can enjoy a great merit derived from the use of the resincomposition of the present invention which is superior inflexibility. Inparticular, the multilayer hose is employed as a fuel hose suitably.Also for this application, it is desirable to use the EVOH (F) as thethermoplastic resin (T1) to be incorporated to the modified EVOH (C).

In addition, when the multilayer structure containing a layer of theresin composition of the present invention is used as a multilayer blowmolded article, a multilayer blow molded article superior in impactresistance can be obtained. As the blow molded article, a multilayercoextrusion blow molded container is preferred. As the multilayer blowmolded container, preferred is one containing the resin composition asan intermediate layer and polyolefin as inner and outer layers. Inparticular, it is preferable to use polyethylene or polypropylene as thepolyolefin. Also for this application, it is desirable to use the EVOH(F) as the thermoplastic resin (T1) to be incorporated to the modifiedEVOH (C).

Moreover, the multilayer blow molded container is suitably used as afuel container for cars or a fuel container for motorcycles. When themultilayer coextrusion blow molded container is used as a fuelcontainer, it is preferable to use a high density polyethylene as thepolyolefin. The high density polyethylene may usually be employed afterbeing selected suitably from commercially available products. Inparticular, from the viewpoints of rigidity, impact resistance,moldability, drawdown resistance, gasoline resistance, etc., the densityof the high density polyethylene is preferably 0.95-0.98 g/cm³ and morepreferably 0.96-0.98 g/cm³. The melt flow rate (MFR) of the high densitypolyethylene used for an inner and outer layers of a multilayer fuelcontainer is preferably 0.01-0.5 g/10 min (at 190° C. under a load of2160 g), and more preferably 0.01-0.1 g/10 min (at 190° C. under a loadof 2160 g).

Another preferable embodiment of the multilayer blow molded container inwhich the resin composition of the present invention and thethermoplastic resin (T2) are laminated is a coinjection stretch blowmolded container.

Thermoplastic polyester (PES) containers as produced through stretchblow molding have various excellent properties including goodtransparency, good mechanical properties and good flavor barrierproperties, and are sanitary and safe as releasing few residual monomersand other harmful additives when employed to be a molded article.Therefore, they have many applications in various fields. However, sincetheir gas barrier properties are not always satisfactory, drinks, foodsand others in them could be stored for only a relatively short period oftime.

In order to overcome the drawback, various methods for combining athermoplastic polyester with an EVOH with good gas barrier properties togive laminated structures have been proposed. Prior to stretch blowing,a parison is first formed. For forming the parison, employed arecoinjection molding, coextrusion molding, multi-stage injection molding,etc. Of those, coinjection molding is characterized in that it may beeffected in simple apparatus, that it gives few scraps such as trimmingsand others, and that the moldings produced through it could have astructure with an EVOH layer completely covered with such as a PES layerand therefore, even though the moldings have no adhesive resin (Ad)layer between the EVOH layer and the PES layer they could be amultilayer containers with good appearance owing to the contact effectby the ambient atmospheric pressure.

However, when containers filled with drinks, foods and others areshocked, for example, by dropping them, the PES layer and the EVOH layerconstituting them are easily delaminated, thereby causing a seriousproblem of worsening the appearance of the containers. In order to solvethis problem, some technologies have been developed. For example,JP-A-11-348194 (EP0949056) discloses a coinjection stretch blow moldedcontainer comprising a thermoplastic polyester layer (layer a) and anethylene-vinyl alcohol copolymer layer (layer b), with the layer a beingkept in direct contact with the both surfaces of the layer b, whereinthe ethylene-vinyl alcohol copolymer satisfies the following formulas(1) and (2) and its differential scanning calorimetry (DSC) gives asingle peak for crystal fusion:25≦ETb≦48  (1)92≦SDb≦99  (2)wherein:

-   ETb indicates the ethylene content (mol %) of the ethylene-vinyl    alcohol copolymer; and-   SDb indicates the degree of saponification (%) of the ethylene-vinyl    alcohol copolymer.

JP-A-2001-277341 (EP1120223) discloses a coinjection stretch blow moldedcontainer which comprises a thermoplastic polyester layer (layer a) andan ethylene-vinyl alcohol copolymer layer (layer b), with the layer abeing kept in direct contact with the both surfaces of the layer b,wherein the above ethylene-vinyl alcohol copolymer is a mixture of twoethylene-vinyl alcohol copolymers (b1, b2) in a ratio by weight (b1/b2)falling between 50/50 and 90/10, and satisfies the following formulas(3) through (8):25≦ETb1≦40  (3)99≦SDb1  (4)35≦ETb2≦48  (5)92≦SDb2≦99  (6)4≦ETb2−ETb1≦23  (7)1≦SDb1−SDb2≦8  (8)wherein:

-   Etb1 indicates the ethylene content (mol %) of the ethylene-vinyl    alcohol copolymer (b1);-   SDb1 indicates the degree of saponification (%) of the    ethylene-vinyl alcohol copolymer (b1);-   Etb2 indicates the ethylene content (mol %) of the ethylene-vinyl    alcohol copolymer (b2); and-   SDb2 indicates the degree of saponification (%) of the    ethylene-vinyl alcohol copolymer (b2

The delamination resistance of a coinjection stretch blow moldedcontainer comprising an EVOH layer and a PES layer has been greatlyimproved by the above-mentioned technologies in comparison with thatconventionally achieved. However, today, the market of the blow moldedcontainer has expanded than before and such containers have come to beused for various applications. As a result of such expansion ofapplications, the blow molded container has increasing demands forfurther improvement in delamination resistance and for improvement intransparency.

The coinjection stretch blow molded container of the present inventionis a multilayer container having a layer of the resin composition of thepresent invention and a layer of a thermoplastic resin (T2). Thus, evenwhen a coinjection stretch blow molded container is applied with impactor the like, the occurrence of delamination between a layer of the resincomposition of the present invention and a layer of a thermoplasticresin (T2) can be prevented effectively. Using such a constitution, itis possible to provide a coinjection stretch blow molded container whichis superior in transparency and gas barrier properties as well as indelamination resistance.

As the resin composition used for coinjection stretch blow moldingcontainer, those previously mentioned can be used. At this time, it isdesirable to use the EVOH (F) as the thermoplastic resin (T1) to beincorporated to the modified EVOH (C). This application particularlyrequires transparency and also requires high barrier properties.Therefore, a smaller difference in ethylene content between the modifiedEVOH (C) and the EVOH (F) is preferred. Specifically, the difference ispreferably up to 2 mol %.

In addition, the use of the resin composition of the present inventioncan also improve the moldability. The moldability can be judged from thecoloration of the appearance of a bottomed parison, the conditions ofoccurrence of gels and streaks in the bottomed parison and the conditionof the edge, which may henceforth be referred to as a leading edge, ofthe resin composition layer in the opening of a container. A schematicview showing a part of a bottomed parison having leading edge in a goodcondition and a schematic view showing a part of a bottomed parisonhaving a leading edge in a bad condition are shown in FIG. 10 and FIG.11, respectively. In the opening 11 of the container, a boundary betweenthe multilayer portion 12 of PES/EVOH and the single layer portion 13 ofPES is the leading edge 14. A desirable condition of the leading edge isa condition where the line of the leading edge is approximatelyhorizontal when the bottomed parison is placed with its bottom portiondown.

In the coinjection stretch blow molded container of the presentinvention, the thermoplastic resin (T2) to be laminated with the resincomposition of the present invention is not specifically limited, but itis preferable to use at least one selected from the group consisting ofpolyester, polypropylene and polyethylene. It is more preferable to usea high density polyethylene as the polyethylene.

So far as the object of the invention is not adversely affected, thelayer of the thermoplastic resin (T2) may be composed of plural layersand may have a layer of a recovery layer; but a layer constitutioncomprising exclusively a layer of the resin composition of the presentinvention and a layer of the thermoplastic resin (T2) is preferred. Morepreferred is a layer constitution in which a layer of the thermoplasticresin (T2) is formed on each side of a layer of the resin composition.Specifically, when a layer of the resin composition of the presentinvention is designated as C, and a layer of the thermoplastic resin isdesignated as T, examples of suitable layer constitutions include(outer)T/C/T(inner), (outer)T/C/T/C/T(inner) and the like. In the abovedescription, (inner) indicates the inner layer, i.e., a layer that willcontact with the content.

As the polyester (PES) to be used as the thermoplastic resin (T2),condensation polymers including aromatic dicarboxylic acids or alkylesters thereof and diols as main components are used. In particular, PESincluding ethylene terephthalate as the main component is preferable inattaining the purpose of the present invention. Concretely, the totalproportion (mol %) of the terephthalic acid unit and the ethylene glycolunit is preferably 70 mol % or more, more preferably 90 mol % or more,of total moles of all the structural units of the PES. If the totalproportion of the terephthalic acid unit and the ethylene glycol unit isless than 70 mol %, the resultant PES is amorphous, so that themechanical strength is insufficient. In addition, when the PES isstretched and formed into a container and the contents are hot-filled inthe container, the thermal shrinkage is so large that it may not be putin practical use. Moreover, when solid-phase polymerization is carriedout to reduce oligomers contained in the resin, the softened resin tendsto stick, which makes production difficult.

If necessary, the above PES may contain a bifunctional compound unitother than the terephthalic acid unit and the ethylene glycol unitwithin the range in which the above-described problems are not caused.The proportion (mol %) thereof is preferably 30 mol % or less, morepreferably 20 mol % or less, and even more preferably 10 mol % or less,of the total moles of all the structural units of the PES. Examples ofsuch a bifunctional compound unit include a dicarboxylic acid unit, adiol unit, and a hydroxycarboxylic acid unit. Such bifunctional compoundunits may either be aliphatic, alicyclic, or aromatic bifunctionalcompound units. Specific examples thereof include a neopentyl glycolunit, a cyclohexanedimethanol unit, a cyclohexanedicarboxylic acid unit,an isophthalic acid unit, and a naphthalenedicarboxylic acid unit.

Among these, an isophthalic acid unit is advantageous since theresultant PES provides a broad range of conditions under which goodproducts can be produced and provides good moldability. This results inan advantage of a lowered defective production rate. This is alsoadvantageous in that the molded article is prevented from whiteningcaused by a suppressed crystallization rate. Also preferable are a1,4-cyclohexanedimethanol unit and 1,4-cyclohexanedicarboxylic acid unitbecause the resultant molded article has even better strength againstdropping. Naphthalene dicarboxylic acid unit is also preferable in thatthe resultant PES has a high glass transition temperature and thethermal resistance is improved, and the ability of absorbing ultravioletradiation can be provided. This is especially useful when the content issusceptible to degradation by ultraviolet radiation. For example, thisis particularly useful when the content is susceptible to degradation byboth oxidation and ultraviolet radiation, such as beer.

In the case of using a polycondensation catalyst during the productionof the PES, a catalyst generally used for production of PES may be used.Examples thereof include: antimony compounds such as antimony trioxide;germanium compounds such as germanium dioxide, germanium tetraethoxide,and germanium tetra-n-butoxide; titanium compounds such as titaniumtetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide,titanium tetraisopropoxide, and titanium tetrabutoxide; and tincompounds such as di-n-butyltin dilaurate, di-n-butyltin oxide, anddibutyltin diacetate. These catalysts may be used alone or incombination of two or more. The amount of the polycondensation catalystused is preferably 0.002 to 0.8% by weight based on the weight ofdicarboxylic acid.

Among these, antimony compounds are preferable in view of the cost ofthe catalyst, and antimony trioxide is especially preferable. On theother hand, germanium compounds are preferable in that the resultant PEShas a good color tone, and germanium dioxide is especially preferable.In view of moldability, the germanium compounds are more preferable thanthe antimony compounds. The PES obtained by the polymerization reactionwith an antimony compound as a catalyst has a higher crystallizationrate than the case using a germanium compound as a catalyst. This meansthat in the case of using an antimony compound, crystallization tends toproceed easily by heating during injection molding or blow molding. Theresultant bottles are likely to generate whitening and may be poor intransparency. The degree of orientation by drawing may also be lowered,and the moldability may deteriorate. This narrows the range ofconditions under which good products can be produced, which tends toincrease the rate of production of defective products.

In particular, when polyethylene terephthalate containing nocopolymerized component other than diethylene glycol units as aby-product is used as the PES used for the present invention, it ispreferable to use a germanium compound as the catalyst to suppress thecrystallization rate when producing the PES.

The method for producing the coinjection blow molded container of thepresent invention including at least one layer made of the resincomposition and at least one PES layer is not specifically defined. Incoinjection blow molding, the container is produced by subjecting acontainer precursor (parison) obtained by coinjection molding to stretchblow molding.

In the coinjection molding, in general, the resins to constitute thelayers of the multilayer structure are guided to a concentric nozzlesfrom two or more injection cylinders and are injected into a single moldsimultaneously or alternately at non-synchronized timings, and oneclamping operation is performed for molding. For example, parisons areproduced by, but not limited to, the following methods: (1) PES layerfor the inner and outer layers is first injected, and then a resincomposition for the intermediate layer is injected to give a three-layercontainer of PES/resin composition/PES; or (2) PES layer for the innerand outer layers is first injected, then a resin composition is injectedwhile, at the same time, or after the injection of the resincomposition, PES layer is again injected to give a five-layer containerof PES/resin composition/PES/resin composition/PES. In addition, in theabove-mentioned layer constitution, an adhesive resin layer may bedisposed between the resin composition layer and the PES layer, ifnecessary.

A multiplayer container containing at least one layer comprising theresin composition and at least one PES layer, which is one of thepreferable embodiments of the present invention, can have a hightransparency and is excellent in ability to maintain the quality of acontent. It, therefore, is best suited to food packaging and the like.Regarding the layer structure of the multilayer container, an adhesiveresin layer may be provided between the resin composition layer and thePES layer as described previously. However, the multilayer container inwhich the PES layers are in direct contact with both surfaces of theresin composition layer is particularly preferable because the followingadvantages of the present invention can be provided to a sufficientextent: a better transparency can be obtained and the resistance toimpact delamination between the resin composition layer and the PESlayer is excellent.

Regarding the conditions for injection molding, the PES is preferablyinjected at a temperature in the range of 250 to 330° C., morepreferably 270 to 320° C., even more preferably 280 to 310° C. If theinjection temperature for PES is lower than 250° C., the PES is notsufficiently melted, and the resulting molded articles may havenon-molten substances (fish eyes), by which their appearance may beworsened, moreover, which may cause the degradation of the mechanicalstrength of the molded articles. In some extreme cases, the screw torquefor the injection of the resin composition may increase, so that themolding machine may have operational malfunctions. If the injectiontemperature for PES exceeds 330° C., PES may be highly decomposed, whichmay lead to a lowered molecular weight, so that the mechanical strengthof the molded articles may be lowered. Moreover, the PES decompositiongives off some vapors of acetaldehyde and the like, and thus theproperties of the materials to be filled in the molded articles may beworsened. Moreover, the oligomers resulting from the PES decompositionmay contaminate the mold significantly, and the resultant moldedarticles may have a poor appearance.

The resin composition of the present invention is preferably injected ata temperature in the range of 160 to 240° C., more preferably 175 to230° C., and still more preferably 185 to 225° C. If the injectiontemperature for the resin composition is lower than 160° C., the resincomposition is not sufficiently melted, and the resulting moldedarticles may have non-molten substances (fish eyes), and thus theirappearance may be worsened. In some extreme cases, the screw torque forthe injection of the resin composition may increase, so that the moldingmachine may have operational malfunctions. On the other hand, if theinjection temperature for the resin composition exceeds 250° C., thedeterioration of the resin composition may proceed, so that the gasbarrier properties of the resin composition may be degraded. Inaddition, the molded articles may be unfavorably colored and containgelled materials, so that the appearance of the resulting moldedarticles may be poor. Moreover, the fluidity will be disordered ordamaged by a decomposition gas and the gelled materials, so that thelayer of the resin composition may have failed areas. In some extremecases, the gelled materials may make it impossible to continue theinjection molding operation. In order to suppress the progress of theoxidation of the composition during melting, it is preferable to sealthe supply hopper with nitrogen.

The temperature of the hot runner parts through which PES and the resincomposition run is preferably in the range of 220 to 300° C., morepreferably 240 to 280° C., still more preferably 250 to 270° C. If thetemperature of the hot runner parts is lower than 220° C., the PES maycrystallize and solidify in the hot runner parts. If so, the moldingoperation will become difficult. If the temperature of the hot runnerparts exceeds 300° C., the deterioration of the resin compositionproceeds so that the gas barrier properties of the resin composition maybe degraded. In addition, the molded articles may be unfavorably coloredand contain gelled materials, so that the appearance of the resultingmolded articles may be poor. Moreover, the fluidity will be disorderedor blocked by the decomposition gas and by the gelled materials, so thatthe layer of the resin composition may have failed areas. In someextreme cases, the gelled materials may make it impossible to continuethe injection molding operation.

The mold temperature is preferably in the range of 0 to 70° C., morepreferably 5 to 50° C., even more preferably 10 to 30° C. With this, thecrystallization of the PES, the modified EVOH (C) or the thermoplasticresin (T1) of the parisons can be suppressed and their uniformstretchabilities are secured, so that molded articles having improveddelamination resistance, transparency, and good shape retentivity can beobtained. If the mold temperature is lower than 0° C., the dew formedaround the mold may worsen the appearance. of the parisons, and thusgood molded articles may not be obtained. On the other hand, if the moldtemperature is higher than 70° C., the crystallization of the PES, themodified EVOH (C) or the thermoplastic resin (T1) which constitutes aparison will not be suppressed and the parison can not be stretcheduniformly. As a result, a molded article to be obtained will havereduced delamination resistance and reduced transparency. Moreover, itwill become difficult to obtain a molded article of an intended shape.

The total thickness of the thus obtained parison is preferably in therange of 2 to 5 mm, and the total thickness of the layer or layers ofthe resin composition of the present invention is preferably in therange of 10 to 500 μm in total.

The above parison is directly in its high-temperature state, or afterhaving been re-heated with heating means such as a block heater, aninfrared heater, or the like, transferred to the next stretch blowingstage. In the stretch blowing stage, the heated parison is stretchedone- to five-fold in the machine direction, and thereafter blown one- tofour-fold with compressed air or the like so that the injection-blownmolded multilayer container of the present invention can be produced.The temperature of the parison is preferably 75 to 150° C., morepreferably 85 to 140° C., even more preferably 90 to 130° C., and stillmore preferably 95 to 120° C. If the temperature of the parison exceeds150° C., the PES may easily crystallize, so that the resultant containermay be whitened and its appearance may become poor. In addition, thedelamination of the stretch-blown container will increase unfavorably.On the other hand, if the temperature of the parison is less than 75°C., the PES may be crazed to be pearly, so that the transparency may belost.

The total thickness of the body part of the thus obtained multilayercontainer of the present invention is generally 100 to 2000 μm,preferably 150 to 1000 μm, and may vary depending on the use of thecontainer. In this case, the total thickness of the layer of the resincomposition of the present invention is preferably in the range of 2 to200 μm, more preferably 5 to 100 μm.

In the manner described above, a multilayer container comprising of alayer of the resin composition of the present invention and a PES layer,which is one preferred embodiment of the present invention, can beobtained. The containers can have a good transparency and also haveexcellent gas barrier properties. The containers are therefore suitablefor contents susceptible to degradation in the presence of oxygen, suchas foods and medicines. Especially, they can be used most suitably ascontainers for beverages such as beer.

In addition, another preferred embodiment of the present invention is amultilayer container containing at least one layer of the resincomposition of the present invention and at least one layer ofpolypropylene. As the polypropylene for use in the present invention,can be used random or block copolymers with other olefin compound suchas ethylene or the like, in addition to homopolypropylene. Among them,copolymers with ethylene are preferred from the viewpoints oftransparency and outer appearance of molded products. In addition, themelt index of the polypropylene is preferably 0.1 to 100 g/10 min (at230° C. under a load of 2160 g), more preferably 0.2 to 50 g/10 min, andmost preferably 0.5 to 20 g/10 min.

As to conditions for injection molding, the molding temperature of thepolypropylene is preferably within the range of 180 to 250° C., and morepreferably 200 to 250° C., from the viewpoint of fluidity of thepolypropylene on melting as well as the appearance and strength of acontainer to be obtained. The production conditions employed forproducing the multilayer parison containing a layer of polypropylene anda layer of the resin composition of the present invention and theproduction conditions employed for the stretch blow molding of themultilayer parison are the same as those employed for the production ofa coinjection blow molded container including a PES layer and a layer ofthe resin composition of the present invention previously described.

The thus obtained coinjection stretch blow molded container of thepresent invention including a polypropylene layer and a layer of theresin composition of the present invention is superior in flavorretainability, organic solvent resistance and delamination resistance.This multilayer container is suitable for storing various contents for along time, and is useful as a container for storing various drinksincluding customarily hot-filled red tea, foods, cosmetics, bloodsamples and the like.

Also in the case of a resin composition obtained by a dynamiccrosslinking treatment (dynamically crosslinked resin composition),which is another embodiment of the present invention, it can be employedas a molding material while being formed in advance into any desiredform such as pellet and powder. Since the dynamically crosslinked resincomposition of the present invention has thermoplasticity, it can bemolded or processed by use of normal molding or processing method andmolding or processing equipment used for typical thermoplastic resin. Asa method for molding or processing, any method may be adopted such asinjection molding, extrusion molding, compression molding, blow molding,calender molding and vacuum molding. Molded articles comprising thedynamically crosslinked resin composition of the present inventionproduced by such methods include those of various shapes such as pipe,sheet, film, disc, ring, bag, bottle, rope and fiber. Laminate orcomposite structures made of the composition and another material arealso included. The adoption of a laminate of the composition and anothermaterial makes it possible to introduce characteristics of the “othermaterials” such as humidity resistance and mechanical properties.

In molded articles comprising at least one layer composed of thedynamically crosslinked resin composition of the present invention andat least one layer of the other material, the other material can beselected appropriately according to the properties required andapplications intended. Examples of the other material includethermoplastic resin such as polyolefin (e.g. high density polyethylene,medium density polyethylene, low density polyethylene, linear lowdensity polyethylene, ethylene-propylene copolymer, polypropylene),ionomers, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acidester copolymer (EEA), polystyrene (PS), vinyl chloride resin (PVC) andvinylidene chloride resin (PVDC).

In molded articles having this laminate structure, an adhesive layer mayexist between a layer of the dynamically crosslinked resin compositionof the present invention and a substrate layer of the other material.The existence of the adhesive layer results in a firm connection of thelayer of the dynamically crosslinked resin composition of the presentinvention and substrate layer of the other material which are disposedon both side thereof. Examples of available adhesives in the adhesivelayer include diene-based polymers modified with acid anhydrides;polyolefins modified with acid anhydrides; and mixtures ofmacromolecular polyols (e.g. polyesterpolyol obtained by polycondensinga glycol compound such as ethylene glycol and propylene glycol with adibasic acid such as adipic acid; and a partially saponificated productof a copolymer of vinyl acetate and vinyl chloride) and polyisocyanatecompounds (e.g. a reaction product in a molar ratio of 1:2 of a glycolcompound such as 1,6-hexamethylene glycol with a diisocyanate compoundsuch as 2,4-tolylenediisocyanate; and a reaction product in a molarratio of 1:3 of a triol compound such as trimethylol propane with adiisocyanate compound such as 2,4-tolylenediisocyanate). For theformation of the laminate structure, known method may be employed suchas coextrusion, coinjection and extrusion coating.

The molded articles comprising the dynamically crosslinked resincomposition of the present invention possess both superior barrierproperties to many kinds of gasses, organic liquids, etc. and superiorflexibility. Therefore, they can be employed in the form of dailynecessaries, packaging materials and machine parts and the like.Examples of applications where the features of the dynamicallycrosslinked resin composition of the present invention can bedemonstrated particularly effectively include packaging materials forfoods and beverages, containers and packings for containers. In themolded articles for use in these applications, the resin composition isonly required to form at least one layer. The molded articles may beselected appropriately from those having a monolayer structure of theresin composition and those having a laminate structure composed of atleast one layer of the resin composition and at least one layer ofanother material. The above-mentioned packaging materials for foods andbeverages, containers and packings for containers are superior inability of preserving contents for a long time because they can preventpermeation of both oxygen gas in the atmosphere and volatile componentscontained in the contents.

The molded articles comprising the dynamically crosslinked resincomposition of the present invention can be reused by being melted atthe time of their disposal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the constitution of the extruder used forproducing the modified EVOHs (C) in Synthesis Examples 1, 5, 6 and 7.

FIG. 2 is a schematic view of the constitution of the extruder used forproducing the modified EVOHs (C) in Synthesis Examples 2, 3 and 4.

FIG. 3 is a ¹H-NMR chart of the modified EVOH (C) obtained in SynthesisExample 1.

FIG. 4 is a ¹H-NMR chart of 1-isopropoxy-2-trifluoroacetoxy-butane,which is one of the model compounds.

FIG. 5 is a ¹H-NMR chart of1-(1-isopropoxy-2-butoxy)-2-trifluoroacetoxy-butane, which is one of themodel compounds.

FIG. 6 is a ¹H-NMR chart of the modified EVOH (C) obtained in SynthesisExample 5.

FIG. 7 is a ¹H-NMR chart of 1-isopropoxy-2,3-ditrifluoroacetoxy-propane,which is one of the model compounds.

FIG. 8 is a ¹H-NMR chart of the modified EVOH (C) obtained in SynthesisExample 3.

FIG. 9 is a diagram showing the outline of the manufacturing process ofa skin packaging material.

FIG. 10 is a schematic view showing part of a bottomed parison having agood leading edge.

FIG. 11 is a schematic view showing part of a bottomed parison having abad leading edge.

FIG. 12 shows the pouring opening with a pull-ring which was injectionmolded in Example 26.

FIG. 13 shows the cap of a container which was injection molded inExample 30.

The numerals in the drawings are explained below.

-   1 Preheating heater-   2 Upper mold-   3 Multilayer film-   4 Lid material-   5 Content (Sliced Ham)-   6 Heat sealer-   7 Lower mold-   8,9 Tube for vacuuming-   10 Table for heat sealer-   11 Opening of container-   12 PES/EVOH multilayer portion-   13 PES monolayer portion-   14 Leading edge-   15 Pouring opening with a pull ring-   16 Ring-   17 Joint of ring and plug-   18 Thin-walled portion for imparting easy-openability-   19 Cap-   20 Pouring opening-   21 Hinge-   22 Lid-   23 Cap of container-   24 Screw channel

BEST MODE FOR CARRYING OUT THE INVENTION

The invention will now be described in more detail with reference to thefollowing Examples, but these Examples should not be construed to limitthe invention at all. The analyses for EVOH (A), modified EVOH (C), EVOH(F) and resin composition were conducted according to the followingmethods.

(1) Ethylene Content and Degree of Saponification of EVOH (A) EVOH (F)

The ethylene content and the degree of saponification of EVOH werecalculated based on the spectra obtained by ¹H-NMR (nuclear magneticresonance) measured using a deuterated dimethyl sulfoxide as a solvent(“JNM-GX-500Model” manufactured by JEOL Ltd. was used for measurement).

(2) Intrinsic Viscosity of EVOH (A)

0.20 g of dry pellets of dry EVOH (A) as a sample were weighedprecisely. The pellets were dissolved in 40 ml of hydrous phenol(water/phenol=15/85: weight ratio) by heating at 60° C. for 3-4 hoursand then measured with an Ostwald viscometer (t0=90 sec) at atemperature of 30° C. The intrinsic viscosity [η] was determined fromthe following formulae.[η]=(2×(ηsp−1nηrel))^(1/2) /C (L/g)ηsp=t/t0−1 (specific viscosity)ηrel=t/t0 (relative viscosity)

-   C: EVOH concentration (g/L)-   t0: The time when a blank (hydrous phenol) passes the viscometer-   t: The time when the hydrous phenol solution containing a dissolved    sample passes the viscometer    (3) Quantification of Contents of Acetic Acid in EVOH (A) and EVOH    (F)

Into 100 ml of ion-exchange water were added 20 g of dried pellets ofEVOH (A) as a sample, and the mixture was heated and extracted at 95° C.for 6 hours. The extract was subjected to neutralization titration witha 1/50 N aqueous NaOH solution using phenolphthalein as an indicator.Thus, the content of acetic acid was quantitatively determined.

(4) Quantifications of Na ion, K ion, Mg ion and Ca ion in EVOH (A),Modified EVOH (C) and EVOH (F)

Into 50 ml of a 0.01 N aqueous hydrochloric acid solution were added 10g of dried pellets of EVOH (A) or modified EVOH (C) as a sample, and themixture was stirred at 95° C. for 6 hours. The resulting solution afterthe stirring was quantitatively analyzed by ion chromatography and theamounts of ions of Na, K, Mg and Ca were determined. The used column wasICS-C25 manufactured by Yokogawa Electric Corporation, and the eluentwas an aqueous solution containing tartaric acid of 5.0 mM and2,6-pyridinedicarboxylic acid of 1.0 mM. For the quantifications,employed were calibration curves prepared for aqueous solutions ofsodium chloride, potassium chloride, magnesium chloride, and calciumchloride.

(5) Quantifications of Phosphate ion and Trifluoromethane Sulfonate ionin EVOH (A), Modified EVOH (C) and EVOH (F)

Into 50 ml of a 0.01 N aqueous hydrochloric acid solution were added 10g of dried pellets of EVOH (A) or modified EVOH (C) as a sample, and themixture was stirred at 95° C. for 6 hours. The resulting solution afterthe stirring was quantitatively analyzed by ion chromatography and theamounts of phosphate ion and trifluoromethane sulfonate ion weredetermined. As the column, used was ICS-A23 (from Yokogawa ElectricCorporation), for which the eluent was an aqueous solution containingsodium carbonate of 2.5 mM and sodium hydrogen carbonate of 1.0 mM. Forthe quantifications, employed were calibration curves prepared foraqueous solutions of sodium dihydrogenphosphate and sodiumtrifluoromethane sulfonate.

(6) Quantification of zinc ion and yttrium ion in Modified EVOH (C)

Into 50 ml of a 0.01 N aqueous hydrochloric acid solution were added 10g of dried pellets of modified EVOH (C) as a sample, and the mixture wasstirred at 95° C. for 6 hours. The aqueous solution after the stirringwas analyzed by ICP emission analysis. As an apparatus, used was Optima4300DV available from Perkin-Elmer Inc. As the measuring wavelength,used were 206.20 nm in the measurement of zinc ion and 360.07 nm in themeasurement of yttrium ion. For the quantifications, employed werecalibration curves prepared for standard solutions of zinc and yttrium,both commercially available.

(7) Melting Points of EVOH (A), Modified EVOH (C) and EVOH (F)

The measurements of the melting points of EVOH (A) and modified EVOH (C)were carried out according to JIS K7121 using a differential scanningcalorimeter (DSC) RDC220/SSC5200H Model (manufactured by SeikoInstruments & Electronics Ltd.). For temperature calibration, used areindium and lead.

(8) Melt Flow Rates (MFR) of EVOH (A), Modified EVOH (C), EVOH (F) andResin Composition

The melt flow rates were measured by use of a melt indexer L244(manufactured by Takara Industry). Concretely, chips of resin formeasurement (EVOH (A), modified EVOH (C), EVOH (F) or resin composition)are filled into a cylinder having an inner diameter of 9.55 mm and alength of 162 mm, melted therein at 190° C. (in Example 10, melted at210° C.). To the resulting resin melt, uniformly applied was a load of aplunger having a weight of 2,160 g and a diameter of 9.48 mm, by whichthe resin was extruded out of the cylinder through the center orificehaving a diameter of 2.1 mm, whereupon the flow rate (g/10 min) of theresin melt being extruded out was measured. The measurement was used asthe melt flow rate (MFR) of the resin.

SYNTHESIS EXAMPLE 1

100 parts by weight of hydrous pellets (water content: 130% (dry basis))of an ethylene-vinyl alcohol copolymer having an ethylene content of 32mol %, a degree of saponification of 99.6% and an intrinsic viscosity of0.0882 L/g were immersed and stirred in 370 parts by weight of anaqueous solution containing acetic acid and potassiumdihydrogenphosphate in amounts of 0.1 g/L and 0.044 g/L, respectively,at 25° C. for 6 hours. The pellets obtained were dried at 105° C. for 20hours, resulting in dry EVOH pellets. The dry EVOH pellets had apotassium content of 8 ppm (in terms of metal element), an acetic acidcontent of 53 ppm, a phosphoric acid compound content of 20 ppm (interms of phosphate radical) and an alkaline earth metal salt content of0 ppm. In addition, the dry pellets had an MFR of 8 g/10 minutes (at190° C., under 2160 g load). The EVOH thus obtained was used as an EVOH(A). Moreover, 1,2-epoxybutane was used as a monofunctional epoxycompound (B) having a molecular weight of not more than 500.

Using a TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by ToshibaMachine Co., Ltd., a screw constitution, vents and a compression inletwere arranged as shown in FIG. 1. Barrel C1 was cooled with water.Barrels C2-C3 were set at 200° C. and barrels C4-C15 were set at 240° C.The extruder was driven at a screw rotation speed of 400 rpm. The EVOH(A) was fed from a resin feed opening of C1 at a rate of 11 kg/hr andwas molten. Then, water and oxygen were removed through vent 1 and1,2-epoxybutane was fed from a compression inlet of C9 at a rate of 2.5kg/hr (pressure during the feed: 6 MPa). After that, unreacted1,2-epoxybutane was removed through vent 2 and a modified EVOH (C) wasthereby obtained. The modified EVOH (C) obtained had an MFR of 2.5 g/10minutes (at 190° C., under 2160 g load) and a melting point of 141° C.

The chemical structure of the thus obtained modified EVOH (C) modifiedwith 1,2-epoxybutane was determined by trifluoroacetylating the modifiedEVOH (C) and then subjecting it to NMR measurement according to thefollowing procedures. At this time, model compounds shown below wereprepared and peaks in the NMR measurement chart of the modified EVOH (C)were assigned through comparison with the NMR measurement charts of themodel compounds.

(1) Trifluoroacetylation and NMR Measurement of Modified EVOH (C)

The modified ethylene-vinyl alcohol copolymer (C) prepared above waspulverized to a particle size not greater than 0.2 mm and 1 g of thispowder was placed into a 100 ml eggplant type flask. Furthermore, 20 gof dichloromethane and 10 g of trifluoroacetic anhydride were added andstirred at room temperature. When one hour had passed since thebeginning of the stirring, the polymer dissolved completely. Afteradditional stirring for one hour since the complete dissolution of thepolymer, the solvent was removed using a rotary evaporator. Theresulting trifluoroacetylated modified ethylene-vinyl alcohol copolymer(C) was dissolved in a concentration of 2 g/L in a mixed solvent ofdeuterate chloroform and trifluoroacetic anhydride (deuteratedchloroform/trifluoroacetic anhydride=2/1 (weight ratio)) and wassubjected to 500 MHz ¹H-NMR measurement using tetramethylsilane as aninternal standard. The NMR measurement chart obtained is shown in FIG.3.

(2) Synthesis of 1-isopropoxy-2-butanol and1-(1-isopropoxy-2-butoxy)-2-butanol

Into a 1 L separable flask equipped with a stirrer and a condenser, 180g of isopropanol and 216 g of epoxybutane were introduced. After fillingwith nitrogen, 1.6 g of sodium was added and then refluxed for 16 hours.After addition of 5 g of phosphoric acid to the mixture,1-isopropoxy-2-butanol (boiling point: 100° C./120 mmHg) and1-(1-isopropoxy-2-butoxy)-2-butanol (boiling point: 105° C./50 mmHg)were obtained by fractional distillation under reduced pressure.1-isopropoxy-2-butanol thus obtained is a model compound in the casewhere one molecule of 1,2-epoxybutane reacted with a hydroxyl group ofEVOH and 1-(1-isopropoxy-2-butoxy)-2-butanol is a model compound in thecase where two or more molecules of 1,2-epoxybutane reacted with ahydroxyl group of EVOH.

(3) Synthesis and NMR Measurement of1-isopropoxy-2-trifluoroacetoxy-butane

After introduction of 530 mg of 1-isopropoxy-2-butanol prepared aboveand 5 g of dichloromethane into a 20 ml eggplant type flask, 1.7 g oftrifluoroacetic anhydride was added. After stirring at room temperaturefor one hour, the solvent was removed using a rotary evaporator. Theresulting 1-isopropoxy-2-trifluoroacetoxy-butane was subjected to 500MHz ¹H-NMR measurement using, as a solvent, a mixed solvent ofdeuterated chloroform and trifluoroacetic anhydride (deuteratedchloroform/trifluoroacetic anhydride=2/1 (weight ratio)). The NMRmeasurement chart obtained is shown in FIG. 4.

(4) Synthesis and NMR Measurement of1-(1-isopropoxy-2-butoxy)-2-trifluoroacetoxy-butane

After introduction of 820 mg of 1-(1-isopropoxy-2-butoxy)-2-butanolprepared above and 5 g of dichloromethane into a 20 ml eggplant typeflask, 1.7 g of trifluoroacetic anhydride was added. After stirring atroom temperature for one hour, the solvent was removed using a rotaryevaporator. The resulting 1-isopropoxy-2-trifluoroacetoxy-butane wassubjected to 500 MHz ¹H-NMR measurement using, as a solvent, a mixedsolvent of deuterated chloroform and trifluoroacetic anhydride(deuterated chloroform/trifluoroacetic anhydride=2/1 (weight ratio)).The NMR measurement chart obtained is shown in FIG. 5.

(5) Analysis of NMR Measurement Chart

As is clear from FIG. 4, there was one signal due to methyl protons inthe range of δ=0.8-1.1 ppm in the ¹H-NMR of1-isopropoxy-2-trifluoroacetoxy-butane. In addition, as is clear fromFIG. 5, there were two signals due to methyl protons in the range ofδ=0.8-1.1 ppm in the ¹H-NMR of1-(1-isopropoxy-2-butoxy)-2-trifluoroacetoxy-butane. On the other hand,as shown in FIG. 3, in the modified EVOH (C) prepared in SynthesisExample 1, there was one signal due to methyl protons in the range ofδ=0.8-1.1 ppm; the modified EVOH (C) prepared in Synthesis Example 1clearly had a structural unit (XII) shown below.

For the chemical structure in the modified EVOH (C) modified with1,2-epoxybutane, the content of each structural unit shown below wasdetermined.

-   w: Ethylene content (mol %)-   x: Content (mol %) of unmodified vinyl alcohol unit-   y: Structural unit (mol %) represented by formula (XII) shown above-   z: Structural unit (mol %) represented by formula (XIII) shown below

There are relations represented by the following equations (1)-(4) forthe w to z defined above.4w+2x+4y+4z=A  (1)3y+2z=B  (2)2z=C  (3)x+y=D  (4)

It is to be noted that in equations (1)-(4), each of A through D is anintegral value of the signal(s) detected within the range shown below inthe ¹H-NMR measurement of the modified EVOH (C).

-   A: Integral value of signal(s) of δ=1.1-2.4 ppm-   B: Integral value of signal(s) of δ=3.1-3.8 ppm-   C: Integral value of signal(s) of δ=4.1-4.5 ppm-   D: Integral value of signal(s) of δ=4.8-5.5 ppm

From equations (1)-(4), the ethylene content of the modified EVOH (C) isdetermined as follows:Ethylene content (mol %) of modified EVOH(C)={w/(w+x+y+z)}×100={(3A−2B−4C−6D)/(3A−2B+2C+6D)}×100

Similarly, the content of structural unit (I) of the modified EVOH (C)is determined as follows:Content (mol %) of structural unit (I) in modified EVOH(C)={(y+z)/(w+x+y+z)}×100={(4B+2C)/(3A−2B+2C+6D)}×100

The modified EVOH (C) prepared in Synthesis Example 1 had an ethylenecontent of 32 mol % and a structural unit (I) content of 4.8 mol %. Theproduction method and characteristics of the resulting modified EVOH (C)are summarized in Table 1.

SYNTHESIS EXAMPLE 2

Into a polyethylene bag, introduced was 5 kg of pellets of an EVOHhaving an ethylene content of 44 mol %, a degree of saponification of99.8%, an intrinsic viscosity of 0.096 L/g and an MFR of 5 g/10 min (at190° C. under a load of 2160 g) {acetic acid content: 53 ppm, sodiumcontent: 1 ppm in terms of metal element, potassium content: 8 ppm interms of metal element, phosphoric acid compound content: 20 ppm interms of phosphate radical}. Then, an aqueous solution was prepared bydissolving 27.44 g (0.125 mol) of zinc acetate dihydrate and 15 g (0.1mol) of trifluoromethane sulfonic acid in 500 g of water. The aqueoussolution was added to the EVOH in the bag. The EVOH to which a catalystsolution had been added in the way described above was heated at 90° C.for 5 hours under occasional shaking with the opening of the bag closed.Thus the EVOH was impregnated with the catalyst solution. The resultingEVOH was dried at 90° C. under vacuum to yield an EVOH including acatalyst (D) containing zinc ion.

As EVOH (A), used was a blend obtained by dry blending 10 parts byweight of the EVOH including a catalyst (D) containing zinc ion to 90parts by weight of the EVOH having an ethylene content of 44 mol %, adegree of saponification of 99.8% and an MFR of 5 g/10 min (at 190° C.under a load of 2160 g) (acetic acid content: 53 ppm, sodium content: 1ppm in terms of metal element, potassium content: 8 ppm in terms ofmetal element, phosphoric acid compound content: 20 ppm in terms ofphosphate radical). Moreover, 1,2-epoxybutane was used as amonofunctional epoxy compound (B) having a molecular weight of not morethan 500.

TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by Toshiba MachineCo., Ltd. was used, and screw constitution, vents and compression inletswere arranged as shown in FIG. 2. Barrel C1 was cooled with water.Barrels C2-C3 were set at 200° C. and barrels C4-C15 were set at 220° C.The extruder was driven at a screw rotation speed of 200 rpm. The EVOH(A) comprising the dry blended mixture and containing the catalyst (D)was fed from a resin feed opening of C1 at a rate of 11 kg/hr. Then, theinner pressure at vent 1 was reduced to 60 mmHg and epoxybutane was fedthrough a compression inlet of C8 at a rate of 2.5 kg/hr (pressureduring the feed: 3.5 MPa). The inner pressure at vent 2 was reduced to200 mmHg to remove unreacted epoxybutane. An aqueous trisodiumethylenediaminetetraacetate trihydrate solution of a concentration of8.2% by weight was added through a compression inlet 2 of C13 at a rateof 0.14 kg/hr.

The mixing ratio of the monofunctional epoxy compounds (B) during themelt-kneading operation was 22.7 parts by weight per 100 parts by weightof the EVOH (A). The catalyst (D) was added in an amount of 2.5 μmol/gin terms of molar number of metal ion based on the weight of the EVOH(A). The ratio (E/D) of the molar number of the catalyst deactivator (E)to the molar number of the metal ion contained in the catalyst (D) was1.

The inner pressure at vent 3 was reduced to 20 mmHg and the moisture wasthereby removed. Thus, a modified EVOH (C) was obtained. Theabove-mentioned modified EVOH (C) obtained had an MFR of 5 g/10 min (at190° C. under a load of 2160 g) and a melting point of 109° C. The zincion content was 150 ppm (2.3 μmol/g) and the alkali metal salt contentwas 168 ppm (7.1 μmol/g) in terms of metal elements [sodium: 160 ppm(6.9 μmol/g); potassium: 8 ppm (0.2 μmol/g)]. The trifluoromethanesulfonic acid ion content was 270 ppm (1.8 μmol/g). The alkali metal ioncontent was 3.9 times (in molar ratio) the trifluoromethane sulfonicacid ion.

The thus obtained modified EVOH (C) had an ethylene content of 44 mol %and a structural unit (I) content of 7 mol %. The production method andcharacteristics of the resulting modified EVOH (C) are summarized inTable 1.

SYNTHESIS EXAMPLE 3

A mixed solution was obtained by mixing 28 parts by weight of zincacetylacetonato monohydrate and 957 parts by weight of1,2-dimethoxyethane. To the resulting mixed solution, 15 parts by weightof trifluoromethane sulfonic acid was added under stirring, yielding asolution containing a catalyst (D). In other words, prepared was asolution in which 1 mol of trifluoromethane sulfonic acid was mixed per1 mol of zinc acetylacetonato monohydrate.

100 parts by weight of hydrous pellets (water content: 130% (dry basis))of an ethylene-vinyl alcohol copolymer having an ethylene content of 32mol %, a degree of saponification of 99.6% and an intrinsic viscosity of0.0882 L/g were immersed and stirred in 370 parts by weight of anaqueous solution containing acetic acid and potassiumdihydrogenphosphate in amounts of 0.1 g/L and 0.044 g/L, respectively,at 25° C. for 6 hours. The pellets obtained were dried at 105° C. for 20hours, resulting in dry EVOH pellets. The dry EVOH pellets had apotassium content of 8 ppm (in terms of metal element), an acetic acidcontent of 53 ppm, a phosphoric acid compound content of 20 ppm (interms of phosphate radical) and an alkaline earth metal salt (Mg salt orCa salt) content of 0 ppm. In addition, the dry pellets had an MFR of 8g/10 min (at 190° C. under a load of 2160 g). The EVOH thus obtained wasused as an EVOH (A). Moreover, epoxypropane was used as a monofunctionalepoxy compound (B) having a molecular weight of not more than 500.

Using a TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by ToshibaMachine Co., Ltd., a screw constitution, vents and compression inletswere arranged as shown in FIG. 2. Barrel C1 was cooled with water.Barrels C2-C15 were set at 200° C. The extruder was driven at a screwrotation speed of 250 rpm. The EVOH (A) was fed from a resin feedopening of C1 at a rate of 11 kg/hr. The inner pressure at vent 1 wasreduced to 60 mmHg. Epoxypropane and the solution of the catalyst (D)prepared by the method mentioned above were fed through a compressioninlet of C8 after mixing thereof so that the epoxypropane and thecatalyst solution were fed at rates of 1.5 kg/hr and 0.22 kg/hr,respectively (pressure during the feed: 3 MPa). Subsequently, unreactedepoxypropane was removed through vent 2 under atmospheric pressure andthen an aqueous trisodium ethylenediaminetetraacetate trihydratesolution of a concentration of 8.2% by weight was added as a catalystdeactivator (E) through a compression inlet 2 of C13 at a rate of 0.11kg/hr.

The mixing ratio of the monofunctional epoxy compounds (B) during themelt-kneading operation was 13.6 part by weight per 100 parts by weightof the EVOH (A). The catalyst (D) was added in an amount of 2 μmol/g, interms of molar number of metal ion based on the weight of the EVOH (A).The ratio (E/D) of the molar number of the catalyst deactivator (E) tothe molar number of the metal ion contained in the catalyst (D) was 1.

The inner pressure at vent 3 was reduced to 20 mmHg and the moisture wasthereby removed. Thus, a modified EVOH (C) was obtained. The modifiedEVOH (C) obtained had an MFR of 7 g/10 min (at 190° C. under a load of2160 g) and a melting point of 132° C. The zinc ion content was 120 ppm(1.9 μmol/g) and the alkali metal salt content was 138 ppm (5.9 μmol/g)in terms of metal elements [sodium: 130 ppm (5.7 μmol/g); potassium: 8ppm (0.2 μmol/g)]. The trifluoromethane sulfonic acid ion content was280 ppm (1.9 μmol/g). The alkali metal ion content was 3.1 times (inmolar ratio) the trifluoromethane sulfonic acid ion.

The chemical structure of the thus obtained modified EVOH (C) modifiedwith epoxypropane was determined by trifluoroacetylating the modifiedEVOH (C) and then subjecting it to NMR measurement according to thefollowing procedures.

The modified EVOH (C) prepared above was pulverized to a particle sizenot greater than 0.2 mm and 1 g of this powder was placed into a 100 mleggplant type flask. Furthermore, 20 g of dichloromethane and 10 g oftrifluoroacetic anhydride were added and stirred at room temperature.When one hour had passed since the beginning of the stirring, themodified EVOH (C) dissolved completely. After additional stirring forone hour since the complete dissolution of the modified EVOH (C), thesolvent was removed using a rotary evaporator. The resultingtrifluoroacetylated modified EVOH (C) was dissolved in a concentrationof 2 g/L in a mixed solvent of deuterated chloroform and trifluoroaceticanhydride (deuterated chloroform/trifluoroacetic anhydride=2/1 (weightratio)) and was subjected to 500 MHz ¹H-NMR measurement usingtetramethylsilane as an internal standard. The NMR measurement chart isshown in FIG. 8.

For the chemical structure in the modified EVOH (C) modified withepoxypropane, the content of each structural unit shown below wasdetermined.

-   w: Ethylene content (mol %):-   x: Content (mol %) of unmodified vinyl alcohol unit-   y: Structural unit (mol %) represented by formula (XVI) shown below-   z: Structural unit (mol %) represented by formula (XVII) shown below

There are relations represented by the following equations (9)-(12) forthe w to z defined above.4w+2x+5y+5z=A  (9)3y+2z=B  (10)2z=C  (11)x+y=D  (12)

It is to be noted that in equations (9)-(12), each of A through D is anintegral value of the signal(s) detected within the range shown below inthe ¹H-NMR measurement of the modified EVOH (C).

-   A: Integral value of signal(s) of δ 1.1-2.5 ppm-   B: Integral value of signal(s) of δ 3.1-4 ppm-   C: Integral value of signal(s) of δ 4.1-4.6 ppm-   D: Integral value of signal(s) of δ 4.8-5.6 ppm

From equations (9)-(12), the ethylene content of the modified EVOH (C)is determined as follows:Ethylene content (mol %) of modified EVOH(C)={w/(w+x+y+z)}×100={(2A−2B−3C−4D)/(2A−2B+C+4D)}×100

Similarly, the content of structural unit (I) of the modified EVOH (C)is determined as follows:Content (mol %) of structural unit (I) in modified EVOH (C)={(y+z)/(w+x+y+z)}×100={(8B+4C)/(6A−6B+3C+12D)}×100

The modified EVOH (C) prepared in Synthesis Example 3 had an ethylenecontent of 32 mol % and a structural unit (I) content of 5.5 mol %. Theproduction method and characteristics of the resulting modified EVOH (C)are summarized in Table 1.

SYNTHESIS EXAMPLE 4

Pellets of an EVOH having an ethylene content of 44 mol %, a degree ofsaponification of 99.8%, an intrinsic viscosity of 0.096 L/g and an MFRof 5 g/10 min (at 190° C. under a load of 2160 g) (acetic acid content:53 ppm, sodium content: 1 ppm in terms of metal element, potassiumcontent: 8 ppm in terms of metal element, phosphoric acid compoundcontent: 20 ppm in terms of phosphate radical) were used as EVOH (A).Epoxypropane was used monofunctional compound (B) having a molecularweight of not more than 500.

Using a TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by ToshibaMachine Co., Ltd., a screw constitution, vents and compression inletswere arranged as shown in FIG. 2. Barrel C1 was cooled with water.Barrels C2-C15 were set at 220° C. The extruder was driven at a screwrotation speed of 250 rpm. The EVOH (A) was fed from a resin feedopening of C1 at a rate of 11 kg/hr. The inner pressure at vent 1 wasreduced to 60 mmHg. Epoxypropane and the solution of the catalyst (D)prepared by the method mentioned above were fed through a compressioninlet of C8 after mixing thereof so that the epoxypropane and thesolution of the catalyst (D) prepared in the same method as SynthesisExample 3 were fed at rates of 2.0 kg/hr and 0.22 kg/hr, respectively(pressure during the feed: 3 MPa). Subsequently, unreacted epoxypropanewas removed through vent 2 under atmospheric pressure and then anaqueous trisodium ethylenediaminetetraacetate trihydrate solution of aconcentration of 8.2% by weight was added as a catalyst deactivator (E)through a compression inlet 2 of C13 at a rate of 0.11 kg/hr.

The mixing ratio of the monofunctional epoxy compounds (B) during themelt-kneading operation was 18.3 parts by weight per 100 parts by weightof the EVOH (A). The catalyst (D) was added in an amount of 2 μmol/g interms of molar number of metal ion based on the weight of the EVOH (A).The ratio (E/D) of the molar number of the catalyst deactivator (E) tothe molar number of the metal ion contained in the catalyst (D) was 1.

The inner pressure at vent 3 was reduced to 20 mmHg and the moisture wasthereby removed. Thus, a modified EVOH (C) was obtained. Theabove-mentioned modified EVOH (C) obtained had an MFR of 5 g/10 min (at190° C. under a load of 2160 g) and a melting point of 105° C. The zincion content was 120 ppm (1.9 μmol/g) and the alkali metal salt contentwas 138 ppm (5.9 μmol/g) in terms of metal elements [sodium: 130 ppm(5.7 μmol/g); potassium: 8 ppm (0.2 μmol/g)]. The trifluoromethanesulfonic acid ion content was 280 ppm (1.9 μmol/g). The alkali metal ioncontent was 3.1 times (in molar ratio) the trifluoromethane sulfonicacid ion. The thus obtained modified EVOH (C) had an ethylene content of44 mol % and a structural unit (I) content of 8 mol %. The productionmethod and characteristics of the resulting modified EVOH (C) aresummarized in Table 1.

SYNTHESIS EXAMPLE 5

A modified EVOH (C) having an MFR of 1.8 g/10 min (at 190° C. under aload of 2160 g) and a melting point of 135° C. was obtained byperforming extrusion under the same conditions as Example 1 exceptchanging, in Example 1, the feed rate of the EVOH (A) from the resinfeed opening of C1 to 15 kg/hr and feeding glycidol in place of1,2-epoxybutane as a monofunctional epoxy compound having a molecularweight of not more than 500 at a rate of 2.5 kg/hr from the compressioninlet of C9.

The chemical structure of the thus obtained modified EVOH (C) modifiedwith glycidol was determined by trifluoroacetylating the modified EVOH(C) and then subjecting it to NMR measurement according to the followingprocedures. At this time, model compounds shown below were prepared andpeaks in the NMR measurement chart of the modified EVOH (C) wereassigned through comparison with the NMR measurement charts of the modelcompounds.

(1) Trifluoroacetylation and NMR Measurement of Modified EVOH (C)

The modified ethylene-vinyl alcohol copolymer (C) prepared above waspulverized to a particle size not greater than 0.2 mm and 1 g of thispowder was placed into a 100-ml eggplant type flask. Furthermore, 20 gof dichloromethane and 10 g of trifluoroacetic anhydride were added andstirred at room temperature. When one hour had passed since thebeginning of the stirring, the polymer dissolved completely. Afteradditional stirring for one hour since the complete dissolution of thepolymer, the solvent was removed using a rotary evaporator. Theresulting trifluoroacetylated modified ethylene-vinyl alcohol copolymer(C) was dissolved in a concentration of 2 g/L in a mixed solvent ofdeuterated chloroform and trifluoroacetic anhydride (deuteratedchloroform/trifluoroacetic anhydride=2/1 (weight ratio)) and wassubjected to 500 MHz ¹H-NMR measurement using tetramethylsilane as aninternal standard. The NMR measurement chart obtained is shown in FIG.6.

(2) Synthesis of 3-isopropoxy-1,2-propanediol

Into a 3-L separable flask equipped with a stirrer and a condenser, 1200g of isopropanol was introduced. Then 4.6 g of sodium was added andheated to 80° C. to dissolve. After complete dissolution of the sodium,300 g of glycidol was dropped at 80° C. over 1 hour. After completion ofthe dropping, stirring was conducted for 3 hours. Then the stirring wasstopped and the mixture was cooled to room temperature. At this time,the mixture separated into an upper layer and a lower layer. The upperlayer was isolated and concentrated by an evaporator. Furthermore,3-isopropoxy-1,2-propanediol (boiling point: 60° C./2 mmHg) was obtainedthrough distillation under reduced pressure.3-Isopropoxy-1,2-propanediol thus obtained is a model compound in thecase where one molecule of glycidol reacted with a hydroxyl group ofEVOH.

(3) Synthesis and NMR Measurement of1-isopropoxy-2,3-ditrifluoroacetoxy-propane

After introduction of 270 mg of 3-isopropoxy-1,2-propane diol preparedabove and 5 g of dichloromethane into a 20 ml eggplant type flask, 1.7 gof trifluoroacetic anhydride was added. After stirring at roomtemperature for one hour, the solvent was removed using a rotaryevaporator. The resulting 1-isopropoxy-2,3-ditrifluoroacetoxy-propanewas subjected to 500 MHz ¹H-NMR measurement using, as a solvent, a mixedsolvent of deuterated chloroform and trifluoroacetic anhydride(deuterated chloroform/trifluoroacetic anhydride=2/1 (weight ratio)).The NMR measurement chart obtained is shown in FIG. 7.

(4) Analysis of NMR Measurement Chart

As is clear from a comparison of FIG. 6 to FIG. 7, the ¹H-NMR of themodel compound 1-isopropoxy-2,3-ditrifluoroacetoxy-propane and the¹H-NMR of the modified EVOH (C) prepared in Synthesis Example 5 hadcommon characteristic signals at δ 3.5-3.9 ppm, 4.5-4.8ppm and 5.3-5.5ppm. When comparing 1-isopropoxy-2,3-ditrifluoroacetoxy-propane as themodel compound to the modified EVOH (C) prepared in Synthesis Example 5,the ratio of an integral value of a signal at δ 3.5-3.9 ppm to anintegral value of a signal at δ 4.5-4.8 ppm was about 3:2 for bothcompounds, which agreed very well with respect to the ratio. The factsdescribed above clearly show that the modified EVOH (C) obtained inSynthesis Example 5 has the structural unit (XIV) shown below.

For the chemical structure in the modified EVOH (C) modified withglycidol, the content of each structural unit shown below wasdetermined.

-   w: Ethylene content (mol %):-   x: Content (mol %) of unmodified vinyl alcohol unit-   y: Structural unit (mol %) represented by formula (XIV) shown above-   z: Structural unit (mol %) represented by formula (XV) shown below

There are relations represented by the following equations (5)-(8) forthe w to z defined above.4w+2x+2y+2z=A  (5)4z=B  (6)2y=C  (7)x+y=D  (8)

It is to be noted that in equations (5)-(8), each of A through D is anintegral value of the signal(s) detected within the range shown below inthe ¹H-NMR measurement of the modified EVOH (C).

-   A: Integral value of signal(s) of δ 1.1-2.4 ppm-   B: Integral value of signal(s) of δ 4.2-4.5 ppm-   C: Integral value of signal(s) of δ 4.5-4.8 ppm-   D: Integral value of signal(s) of δ 4.8-5.6 ppm

From equations (5)-(8), the ethylene content of the modified EVOH (C) isdetermined as follows:Ethylene content (mol %) of modified EVOH(C)={w/(w+x+y+z)}×100={(2A−B−4D)/(2A+B+4D)}×100

Similarly, the content of structural unit (I) of the modified EVOH (C)is determined as follows:Content (mol %) of structural unit (I) in modified EVOH(C)={(y+z)/(w+x+y+z)}×100={(2B+4C)/(2A+B+4D)}×100

The modified EVOH (C) prepared in Synthesis Example 5 had an ethylenecontent of 32 mol % and a structural unit (I) content of 5 mol %. Theproduction method and characteristics of the resulting modified EVOH (C)are summarized in Table 1.

SYNTHESIS EXAMPLE 6

100 parts by weight of hydrous pellets (water content: 130% (dry basis))of an ethylene-vinyl alcohol copolymer having an ethylene content of 44mol %, a degree of saponification of 99.6% and an intrinsic viscosity of0.0855 L/g were immersed and stirred in 370 parts by weight of anaqueous solution containing acetic acid and potassiumdihydrogenphosphate in amounts of 0.12 g/L and 0.044 g/L, respectively,at 25° C. for 6 hours. The pellets obtained were dried at 105° C. for 20hours, resulting in dry EVOH pellets. The dry EVOH pellets had apotassium content of 8 ppm (in terms of metal element), an acetic acidcontent of 62 ppm, a phosphoric acid compound content of 20 ppm (interms of phosphate radical) and an alkaline earth metal salt content of0 ppm. In addition, the dry pellets had an MFR of 12 g/10 min (at 190°C. under a load of 2160 g). The EVOH thus obtained was used as an EVOH(A). Moreover, glycidol was used as an epoxy compound (B).

Using a TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by ToshibaMachine Co., Ltd., a screw constitution, vents and a compression inletwere arranged as shown in FIG. 1. Barrel C1 was cooled with water.Barrels C2-C3 were set at 200° C. and barrels C4-C15 were set at 240° C.The extruder was driven at a screw rotation speed of 400 rpm. The EVOH(A) was fed from a resin feed opening of C1 at a rate of 15 kg/hr andwas molten. Then, water and oxygen were removed through vent 1 andglycidol was fed through a compression inlet of C9 at a rate of 2.5kg/hr (pressure during the feed: 7 MPa). After that, unreacted glycidolwas removed through vent 2, yielding a modified EVOH (C) comprising amodified EVOH (C) having an MFR of 1.6 g/10 min (at 190° C. under a loadof 2160 g), a structural unit (I) content of 6 mol % and a melting pointof 127° C. The production method and characteristics of the resultingmodified EVOH (C) are summarized in Table 1.

SYNTHESIS EXAMPLE 7

An EVOH modified with bisphenol A diglycidyl ether having an MFR of 2.5g/10 min (at 190° C. under a load of 2160 g) was obtained by performingextrusion under the same conditions as Synthesis Example 1 exceptchanging, in Synthesis Example 1, the feed rate of the EVOH (A) from theresin feed opening of C1 to 15 kg/hr and feeding bisphenol A diglycidylether (manufactured by Tokyo Kasei Kogyo Co., Ltd.) at a rate of 120g/hr in place of epoxybutane from the compression inlet of C9. Theproduction method and characteristics of the resulting modified EVOH aresummarized in Table 1.

TABLE 1 Blending MFR of amount of Metal ion Melt Structural EVOH (A) (B)*1) of kneading Ethylene unit (I) Melting MFR (g/10 Epoxy (part bycatalyst temperature content content point (g/10 min) compound (B)weight) (D) (° C.) (mol %) (mol %) (° C.) min) Synthesis 8 1,2- 22.7 No240 32 4.8 141 2.5 Example 1 Epoxybutane catalyst Synthesis 5 1,2- 22.7Zinc ion 220 44 7 109 5 Example 2 Epoxybutane Synthesis 8 Epoxypropane13.6 Zinc ion 200 32 5.5 132 7 Example 3 Synthesis 5 Epoxypropane 18.3Zinc ion 220 44 8 105 5 Example 4 Synthesis 8 Glycidol 16.7 No 240 32 5135 1.8 Example 5 catalyst Synthesis 12 Glycidol 16.7 No 240 44 6 1271.6 Example 6 catalyst Synthesis 8 *2) 0.8 No 240 32 *3) *3) 2.5 Example7 catalyst *1) The amount of epoxy compound (B) in part by weight basedon 100 parts by weight of EVOH (A). *2) Bisphenol A diglycidyl ether *3)Not measured

EXAMPLE 1

(1) Production of Resin Composition

80 parts by weight of EVOH (F) having an ethylene content of 32 mol %, adegree of saponification of 99.9%, a melt flow rate (at 190° C. under aload of 2160 g) of 1.6 g/10 min and a melting point of 183° C. and 20parts by weight of modified EVOH (C) prepared in Synthesis Example 1were dry blended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then hot air drying was carried out at 80° C. for 16 hour,yielding a resin composition. The contents of phosphoric acid compound(in terms of phosphate radical), acetic acid, and Na ion (in terms ofmetal element) in the EVOH (F) were measured to be 50 ppm, 300 ppm and200 ppm, respectively. The melt flow rate (at 190° C. under a load of2160 g) of the resin composition was 1.9 g/10 min.

(2) Preparation of Monolayer Film

Using the thus-obtained resin composition, film formation was carriedout under the extrusion conditions shown below by means of a filmforming machine composed of a 40φ extruder (PLABOR GT-40-A manufacturedby Research Laboratory Of Plastics Technology Co., Ltd.) and a T-die.Thus, a monolayer film of 25 μm in thickness was obtained.

-   Type: Single screw extruder (non-vent type)-   L/D: 24-   Bore diameter: 40 mmφ-   Screw: Single-thread full-flight type, nitrided surface steel-   Screw rotation speed: 40 rpm-   Die: Coat hanger die of 550 mm in width-   Gap between lips: 0.3 mm-   Temperatures Set for Cylinders and Die:    C1/C2/C3/adaptor/die=180/200/210/210/210 (° C.)

Using the monolayer film prepared above, an oxygen transmission rate, acarbon dioxide gas transmission rate, a Young's modulus, a tensilestrength at yield, a tensile elongation at break and a haze weremeasured and a flexing resistance test was carried out according tofollowing methods shown below.

(2-1) Measurement of Oxygen Transmission Rate

The monolayer film prepared above was moisture conditioned at 20° C. and65% RH for 5 days. For two samples of the moisture-conditioned monolayerfilm, oxygen transmission rates were measured using an apparatus, MOCONOX-TRAN 2/20, manufactured by Modern Control, Inc. according to JISK7126 (Equal Pressure Method) under a 20° C. and 65% RH condition andthe average thereof was calculated. The oxygen transmission rate was 0.5cc·20 μm/m²·day·atm and a good gas barrier property was shown.

(2-2) Measurement of Carbon Dioxide Gas Transmission Rate

The monolayer film prepared above was moisture conditioned at 20° C. and65% RH for 5 days. For two samples of the moisture-conditioned film,carbon dioxide gas transmission rates were measured using an apparatus,MOCON PERMA-TRANC-IV, manufactured by Modern Control, Inc. according toJIS K7126 (Equal Pressure Method) under a 20° C.-65% RH condition andthe average thereof was calculated. The carbon dioxide gas transmissionrate was 2.2 cc·20 μm/m²·day·atm and a good gas barrier property wasshown.

(2-3) Measurement of Young's Modulus

The monolayer film prepared above was moisture conditioned in anatmosphere of 23° C. and 50% RH for 7 days, and then a specimen in theform of a strip 15 mm wide was made. Using this sample film, a Young'smodulus was measured under conditions, a span of 50 mm and a tensilespeed of 5 mm/min by an Autograph AGS-H manufactured by Shimadzu Corp.Measurements were conducted for ten samples and the average thereof wascalculated. The Young's modulus was 176 kgf/mm².

(2-4) Measurements of Tensile Strength at Yield and Tensile Elongationat Break

The monolayer film prepared above was moisture conditioned in anatmosphere of 23° C. and 50% RH for 7 days, and then a specimen in theform of a strip 15 mm wide was made. Using this sample film, a tensilestrength at yield and a tensile elongation at break were measured underconditions, a span of 50 mm and a tensile speed of 500 mm/min by anAutograph AGS-H manufactured by Shimadzu Corp. Measurements wereconducted for ten samples and the average thereof was calculated. Thetensile strength at yield and the tensile elongation at break were 6.4kgf/mm² and 306%, respectively.

(2-5) Measurement of Haze

Using the monolayer film prepared above, a measurement of haze wasconducted according to JIS D8741 using an integral type H.T.R metermanufactured by Nihon Seimitsu Kogaku Co., Ltd. The haze was 0.1%, and avery good transparency was shown.

(2-6) Evaluation of Flexing Resistance

From the monolayer film prepared above, fifty films of 21 cm×30 cm werecut out. Following moisture conditioning at 20° C. and 65% RH for 5days, every cut film was flexed 50 times, 75 times, 100 times, 125times, 150 times, 175 times, 200 times, 225 times, 250 times or 300times using a Gelbo Flex Tester manufactured by Rigaku Kogyo Co., Ltd.according to ASTM F392-74. Then, the number of pinholes in the film wasmeasured. For each number of flextures, measurements were conducted fivetimes and the average thereof was used as the number of pinholes. Theabove measurements were plotted with numbers of flexures (P) as abscissaagainst numbers of pinholes (N) as ordinate. The number of flextures atwhich one pinhole is formed (Np1) is determined to a two-digitsignificant figure by extrapolation. As a result, Np1 was 90 times andan extremely superior flexing resistance was shown.

(3) Preparation of Monolayer Sheet

Using the thus-obtained resin composition, film formation was carriedout under the extrusion conditions shown below by means of a filmforming machine composed of a 40φ extruder (PLABOR GT-40-A manufacturedby RESEARCH LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.) and a T-die.Thus, a monolayer sheet of 150 μm in thickness was obtained.

-   Type: Single screw extruder (non-vent type)-   L/D: 24-   Bore diameter: 40 mmφ-   Screw: Single-thread full-flight type, nitrided surface steel-   Screw rotation speed: 100 rpm-   Die: Coat hanger die of 550 mm in width-   Gap between lips: 0.3 mm-   Temperatures Set for Cylinders and Die:    C1/C2/C3/adaptor/die=180/200/210/210/210 (° C.)    (3-1) Evaluation of Stretchability of Monolayer Sheet

The monolayer sheet prepared above was put in a pantograph type biaxialstretching machine manufactured by Toyo Seiki Seisaku-Sho, Ltd. and wassubjected to simultaneous biaxial stretching at 100° C. at a draw ratioof every 0.25×0.25 time within the draw ratio range of from 2.0×2.0 timeto 5.0×5.0 time. The maximum draw ratio at which the sheet was able tobe stretched well without causing breakage in the sheet stretched was4.0×4.0 time.

(4) Preparation of Multilayer Sheet

Next, using the resin composition obtained, a multilayer sheet(polystyrene resin layer/adhesive resin layer/resin compositionlayer/adhesive resin layer/polystyrene resin layer) was prepared bymeans of a three-kind five-layer coextrusion machine shown later undercoextrusion molding conditions also described layer. The sheetconstitution is as follows: the layers of the polystyrene resin(“Idemitsu Styrol ET-61” manufactured by Idemitsu Chemical Co., Ltd.),both outermost layers: 425 μm each; the layers of the adhesive resin(“ADMER SF600” manufactured by Mitsui Chemicals, Inc.): 50 μm each; andthe layer of the resin composition: 50 μm.

Layer Constitution:

-   polystyrene resin/adhesive resin/resin composition/adhesive    resin/polystyrene resin-   (thickness 425/50/50/50/425; unit: μm)    Specifications of Extruder and Extrusion Temperature for Each Resin:    Polystyrene Resin:-   65φ extruder, model 20VSE-65-22 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=150/180/210/210/220° C.    Adhesive Resin:-   40φ extruder, model 10VSE-40-22 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=130/180/210/210/220° C.    Resin Composition:-   40φ extruder, model VSVE-40-24 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=175/210/210/210/210° C.    Specifications of T-Die:-   for 600 mm-wide three-kind five-layer extrusion (manufactured by    RESEARCH LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.)    AD/Die=220/220° C.-   Temperature of cooling roll: 80° C.-   Drawing speed: 1.2 m/min    (4-1) Evaluation of Stretchability of Multilayer Sheet

The multilayer sheet prepared above was put in a pantograph type biaxialstretching machine manufactured by Toyo Seiki Seisaku-Sho, Ltd. and wassubjected to simultaneous biaxial stretching at a draw ratio of 4×4 at120° C. The film appearance after the drawing was evaluated according tothe following criteria.

Judgment: Criteria

-   A: There is neither unevenness nor local thickness deviation.-   B: There is slight unevenness, but there is no local thickness    deviation.-   C: There are slight unevenness and slight local thickness deviation,    but the film can be used practically.-   D: There are severe unevenness and great local thickness deviation.-   E: The film has a tear.

The film of this Example after the stretching had no unevenness or nolocal thickness deviation and, therefore, was rated as A.

The components and the like of the resin composition and the evaluationresults and the like of the film and sheet are summarized in Table 2 andTable 3, respectively.

EXAMPLE 2

80 parts by weight of EVOH (F) the same as that used in Example 1 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 2were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 2.2 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 3

80 parts by weight of EVOH (F) the same as that used in Example 1 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 3were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 2.3 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 4

50 parts by weight of EVOH (F) the same as that used in Example 1 and 50parts by weight of modified EVOH (C) obtained in Synthesis Example 3were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 3.5 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 5

80 parts by weight of EVOH (F) having an ethylene content of 44 mol %, adegree of saponification of 99.9%, a melt flow rate (at 190° C. under aload of 2160 g) of 5.5 g/10 min, and a melting point of 165° C. and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 3were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The contents of phosphoric acid compound (in terms ofphosphate radical), acetic acid, and Na ion (in terms of metal element)in the EVOH (F) were measured to be 50 ppm, 200 ppm and 120 ppm,respectively. The melt flow rate (at 190° C. under a load of 2160 g) ofthe resin composition was 6.0 g/10 min. Using the thus obtained resincomposition, a monolayer film, a monolayer sheet and a multilayer sheetwere produced in the same manner as Example 1. These were measured fortheir oxygen transmission rate, carbon dioxide gas transmission rate andhaze and were evaluated for their flexing resistance and stretchability.The components and the like of the resin composition and the evaluationresults and the like of the film are summarized in Table 2 and Table 3,respectively.

EXAMPLE 6

90 parts by weight of EVOH (F) the same as that used in Example 1 and 10parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 2.0 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 7

80 parts by weight of EVOH (F) the same as that used in Example 1 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 2.2 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 8

50 parts by weight of EVOH (F) the same as that used in Example 1 and 50parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 3.0 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 9

80 parts by weight of EVOH (F) the same as that used in Example 5 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 5.6 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 10

80 parts by weight of EVOH (F) having an ethylene content of 27 mol %, adegree of saponification of 99.9%, a melt flow rate (at 210° C. under aload of 2160 g) of 3.9 g/10 min, and a melting point of 191° C. and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The contents of phosphoric acid compound (in terms ofphosphate radical), acetic acid, and Na ion (in terms of metal element)in the EVOH (F) were measured to be 50 ppm, 300 ppm and 200 ppm,respectively. The melt flow rate (at 210° C. under a load of 2160 g) ofthe resin composition was 5.1 g/10 min. Using the thus obtained resincomposition, a monolayer film, a monolayer sheet and a multilayer sheetwere produced in the same manner as Example 1. These were measured fortheir oxygen transmission rate, carbon dioxide gas transmission rate andhaze and were evaluated for their flexing resistance and stretchability.The components and the like of the resin composition and the evaluationresults and the like of the film are summarized in Table 2 and Table 3,respectively.

EXAMPLE 11

80 parts by weight of EVOH (F) having an ethylene content of 32 mol %, adegree of saponification of 99.9%, a melt flow rate (at 190° C. under aload of 2160 g) of 1.6 g/10 min, and a melting point of 183° C. and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 4were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The contents of phosphoric acid compound (in terms ofphosphate radical), acetic acid, and Na ion (in terms of metal element)in the EVOH (F) were measured to be 50 ppm, 300 ppm and 200 ppm,respectively. In addition, the boron content thereof was 180 ppm. Themelt flow rate (at 190° C. under a load of 2160 g) of the resincomposition was 2.2 g/10 min. Using the thus obtained resin composition,a monolayer film, a monolayer sheet and a multilayer sheet were producedin the same manner as Example 1. These were measured for their oxygentransmission rate, carbon dioxide gas transmission rate and haze andwere evaluated for their flexing resistance and stretchability. Thecomponents and the like of the resin composition and the evaluationresults and the like of the film are summarized in Table 2 and Table 3,respectively.

EXAMPLE 12

80 parts by weight of EVOH (F) the same as that used in Example 1 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 5were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 1.8 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

EXAMPLE 13

80 parts by weight of EVOH (F) the same as that used in Example 5 and 20parts by weight of modified EVOH (C) obtained in Synthesis Example 6were dry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 4.5 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their flexing resistance andstretchability. The components and the like of the resin composition andthe evaluation results and the like of the film are summarized in Table2 and Table 3, respectively.

COMPARATIVE EXAMPLE 1

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the EVOH (F) used inExample 1 in place of the resin composition. These were measured fortheir oxygen transmission rate, carbon dioxide gas transmission rate andhaze and were evaluated for their stretchability. The physicalproperties and the like of the EVOH (F) and the evaluation results andthe like of the film are summarized in Table 2 and Table 3,respectively.

The flexing resistance was evaluated in the manner described below.Using the EVOH (F) pellets used in Example 1, film formation was carriedout at an extrusion temperature of from 180 to 210° C. and a T-dietemperature of 210° C. by means of a film forming machine composed of a40φ extruder and a T-die. Thus, a monolayer film of 25 μm in thicknesswas obtained. From the EVOH monolayer film prepared above, forty films21 cm×30 cm were cut out. Following moisture conditioning at 20° C. and65% RH for 5 days, every cut film was flexed 25 times, 30 times, 35times, 40 times, 50 times, 60 times, 80 times or 100 times using a GelboFlex Tester manufactured by Rigaku Kogyo Co., Ltd. according to ASTMF392-74. And then the number of pinholes in the film was measured. Foreach number of flextures, measurements were conducted five times and theaverage thereof was used as the number of pinholes. The abovemeasurements were plotted with numbers of flexures (P) as abscissaagainst numbers of pinholes (N) as ordinate. The number of flextures atwhich one pinhole is formed (Np1) is determined by extrapolation. Np1 ofthe film of this Comparative Example was 34 times.

COMPARATIVE EXAMPLE 2

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the EVOH (F) used inExample 5 in place of the resin composition. These were measured fortheir oxygen transmission rate, carbon dioxide gas transmission rate andhaze and were evaluated for their stretchability. They were evaluatedfor their flexing resistance in the same manner as ComparativeExample 1. The physical properties and the like of the EVOH (F) and theevaluation results and the like of the film are summarized in Table 2and Table 3, respectively.

COMPARATIVE EXAMPLE 3

80 parts by weight of EVOH (F) the same as that used in Example 1 and 20parts by weight of modified EVOH obtained in Synthesis Example 7 weredry blended. Then, twin screw extrusion, pelletization and hot airdrying were conducted in the same manner as Example 1, resulting in aresin composition. The melt flow rate (at 190° C. under a load of 2160g) of the resin composition was 1.9 g/10 min. Using the thus obtainedresin composition, a monolayer film, a monolayer sheet and a multilayersheet were produced in the same manner as Example 1. These were measuredfor their oxygen transmission rate, carbon dioxide gas transmission rateand haze and were evaluated for their stretchability. They wereevaluated for their flexing resistance in the same manner as ComparativeExample 1. The components and the like of the resin composition and theevaluation results and the like of the film are summarized in Table 2and Table 3, respectively.

COMPARATIVE EXAMPLE 4

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the modified EVOH (C)obtained in Synthesis Example 1 in place of the resin composition. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchabilityand flexing resistance. The physical properties and the like of themodified EVOH (C) and the evaluation results and the like of the filmare summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 5

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the modified EVOH (C)obtained in Synthesis Example 2 in place of the resin composition. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchabilityand flexing resistance. The physical properties and the like of themodified EVOH (C) and the evaluation results and the like of the filmare summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 6

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the modified EVOH (C)obtained in Synthesis Example 3 in place of the resin composition. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchabilityand flexing resistance. The physical properties and the like of themodified EVOH (C) and the evaluation results and the like of the filmare summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 7

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the modified EVOH (C)obtained in Synthesis Example 5 in place of the resin composition. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchabilityand flexing resistance. The physical properties and the like of themodified EVOH (C) and the evaluation results and the like of the filmare summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 8

A monolayer film, a monolayer sheet and a multilyer sheet were preparedin the same manner as Example 1 except using only the modified EVOH (C)obtained in Synthesis Example 6 in place of the resin composition. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchabilityand flexing resistance. The physical properties and the like of themodified EVOH (C) and the evaluation results and the like of the filmare summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 9

80 parts by weight of the EVOH (F) used in Example 1 and 20 parts byweight of EVOH of a low degree of saponification which had an ethylenecontent of 32 mol %, a degree of saponification of 97.0%, an MFR of 1.2g/10 min (at 190° C. under a load of 2160 g) and a melting point of 171°C. were dry blended. Then, twin screw extrusion, pelletization and hotair drying were conducted in the same manner as Example 1, resulting ina resin composition. The contents of phosphoric acid compound (in termsof phosphate radical), acetic acid, and Na ion (in terms of metalelement) in the EVOH of a low degree of saponification used weremeasured to be 50 ppm, 300 ppm and 200 ppm, respectively. The melt flowrate (at 190° C. under a load of 2160 g) of the resin composition was1.7 g/10 min. Using the thus obtained resin composition, a monolayerfilm, a monolayer sheet and a multilayer sheet were produced in the samemanner as Example 1. These were measured for their oxygen transmissionrate, carbon dioxide gas transmission rate and haze and were evaluatedfor their flexing resistance and stretchability. The components and thelike of the resin composition and the evaluation results and the like ofthe film are summarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 10

50 parts by weight of the EVOH (F) used in Example 1 and 50 parts byweight of the EVOH of a low degree of saponification used in ComparativeExample 9 were dry blended. Then, twin screw extrusion, pelletizationand hot air drying were conducted in the same manner as Example 1,resulting in a resin composition. The melt flow rate (at 190° C. under aload of 2160 g) of the resin composition was 1.6 g/10 min. Using thethus obtained resin composition, a monolayer film, a monolayer sheet anda multilayer sheet were produced in the same manner as Example 1. Thesewere measured for their oxygen transmission rate, carbon dioxide gastransmission rate and haze and were evaluated for their stretchability.They were evaluated for their flexing resistance in the same manner asComparative Example 1. The components and the like of the resincomposition and the evaluation results and the like of the film aresummarized in Table 2 and Table 3, respectively.

COMPARATIVE EXAMPLE 11

80 parts by weight of the EVOH (F) used in Example 1 and 20 parts byweight of EVOH of a low degree of saponification which had an ethylenecontent of 44 mol %, a degree of saponification of 96.5%, an MFR of 5.0g/10 min (at 190° C. under a load of 2160 g) and a melting point of 157°C. were dry blended. Then, twin screw extrusion, pelletization and hotair drying were conducted in the same manner as Example 1, resulting ina resin composition. The contents of phosphoric acid compound (in termsof phosphate radical), acetic acid, and Na ion (in terms of metalelement) in the EVOH of a low degree of saponification used weremeasured to be 50 ppm, 200 ppm and 120 ppm, respectively. The melt flowrate (at 190° C. under a load of 2160 g) of the resin composition was2.2 g/10 min. Using the thus obtained resin composition, a monolayerfilm, a monolayer sheet and a multilayer sheet were produced in the samemanner as Example 1. These were measured for their oxygen transmissionrate, carbon dioxide gas transmission rate and haze and were evaluatedfor their stretchability. They were evaluated for their flexingresistance in the same manner as Comparative Example 1. The componentsand the like of the resin composition and the evaluation results and thelike of the film are summarized in Table 2 and Table 3, respectively.

TABLE 2 Modified EVOH (C) Structural EVOH (F) Resin composition unit (I)Ethylene Melting Ethylene Melting Weight MFR Epoxy compound contentcontent point MFR content point MFR ratio (g/10 (B) (mol %) (mol %) (°C.) (g/10 min) (mol %) (° C.) (g/10 min) (C)/(F) min) Example 11,2-Epoxybutane 4.8 32 141 2.5 32 183 1.6 20/80 1.9 Example 21,2-Epoxybutane 7 44 109 5 32 183 1.6 20/80 2.2 Example 3 Epoxypropane5.5 32 132 7 32 183 1.6 20/80 2.3 Example 4 Epoxypropane 5.5 32 132 7 32183 1.6 50/50 3.5 Example 5 Epoxypropane 5.5 32 132 7 44 165 5.5 20/806.0 Example 6 Epoxypropane 8 44 105 5 32 183 1.6 10/90 2.0 Example 7Epoxypropane 8 44 105 5 32 183 1.6 20/80 2.2 Example 8 Epoxypropane 8 44105 5 32 183 1.6 50/50 3.0 Example 9 Epoxypropane 8 44 105 5 44 165 5.520/80 5.6 Example 10 Epoxypropane 8 44 105 5 27 191 3.9 *1) 20/80 5.1*1) Example 11 Epoxypropane 8 44 105 5 32 *2) 183 1.6 20/80 2.2 Example12 Glycidol 5 32 135 1.8 32 183 1.6 20/80 1.8 Example 13 Glycidol 6 44127 1.6 44 165 5.5 20/80 4.5 Comparative — — — — — 32 183 1.6  0/100 1.6Example 1 Comparative — — — — — 44 165 5.5  0/100 5.5 Example 2Comparative *3) *4) 32 *4) 2.5 32 183 1.6 20/80 1.9 Example 3Comparative 1,2-Epoxybutane 4.8 32 141 2.5 — — — 100/0  2.5 Example 4Comparative 1,2-Epoxybutane 7 44 109 5 — — — 100/0  5 Example 5Comparative Epoxypropane 5.5 32 132 7 — — — 100/0  7 Example 6Comparative Glycidol 5 32 135 1.8 — — — 100/0  1.8 Example 7 ComparativeGlycidol 6 44 127 1.6 — — — 100/0  1.6 Example 8 Comparative EVOH of lowdegree of 32 171 1.2 32 183 1.6 20/80 1.7 Example 9 saponificationComparative EVOH of low degree of 32 171 1.2 32 183 1.6 50/50 1.6Example 10 saponification Comparative EVOH of low degree of 44 157 5 32183 1.6 20/80 2.2 Example 11 saponification *1) Measured at 210° C. *2)Boric acid treatment *3) Bisphenol A diglycidyl ether *4) Not measured

TABLE 3 Carbon Maximum stretch Oxygen dioxide gas Tensile Flexingmagnification transmission transmission Young's strength at Tensileresistance of monolayer Stretchability rate rate modulus yieldelongation Haze (Np1) sheet of multilayer *1) *1) (kgf/mm²) (kgf/mm²) atbreak (%) (%) *2) (time) sheet Example 1 0.5 2.2 176 6.4 306 0.1 90 4.0× 4.0 A Example 2 0.6 2.6 172 6.3 323 0.3 160 4.25 × 4.25 A Example 30.4 1.7 168 6.4 313 0.1 90 3.75 × 3.75 A Example 4 0.7 2.9 113 4.1 3620.1 150 3.75 × 3.75 A Example 5 0.5 2.0 120 5.4 387 0.2 270 3.25 × 3.25A Example 6 0.5 1.9 186 7.1 305 0.3 120 3.75 × 3.75 A Example 7 0.7 2.6167 5.6 329 0.3 190 4.25 × 4.25 A Example 8 2.3 9.0 111 4.7 308 0.4 2204.0 × 4.0 A Example 9 2.5 9.2 119 5.5 383 0.1 300 3.25 × 3.25 A Example10 0.3 1.3 142 5.4 317 0.3 180 4.0 × 4.0 A Example 11 0.7 2.7 167 6.4330 0.2 180 4.25 × 4.25 A Example 12 0.4 1.4 168 6.5 310 0.1 110 3.5 ×3.5 B Example 13 1.7 6.5 119 5.6 362 0.1 290 3.75 × 3.75 A Comparative0.3 1.8 205 7.9 191 0.4 34 2.25 × 2.25 E Example 1 Comparative 1.5 6.2145 7.0 224 0.3 47 Unstretchable E Example 2 Comparative 1.0 4.7 206 8.0199 0.6 37 2.25 × 2.25 E Example 3 Comparative 2.5 11 46 5.3 278 0.1 1603.75 × 3.75 B Example 4 Comparative 10.0 37 36 3.1 333 0.1 300 4.5 × 4.5A Example 5 Comparative 1.5 6.0 31 3.9 302 0.1 160 4.0 × 4.0 A Example 6Comparative 0.7 3.7 22 3.1 292 0.1 180 3.75 × 3.75 B Example 7Comparative 2.7 13 15 3.4 336 0.1 220 4.0 × 4.0 A Example 8 Comparative0.5 2.5 203 7.5 206 0.4 37 2.25 × 2.25 E Example 9 Comparative 0.9 3.7201 6.8 229 0.3 41 2.25 × 2.25 D Example 10 Comparative 0.6 2.9 192 7.3216 1.0 40 2.25 × 2.25 D Example 11 *1) Unit: cc · 20 μm/m² · day · atm*2) Np1: The number of flexures until one pinhole is formed.

As shown above, the resin compositions comprising an unmodified EVOH (F)and a modified EVOH (C) having a structural unit (I) (Examples 1 to 13)have greatly improved flexibilities, flexing resistances andstretchabilities despite their slightly increased oxygen transmissionrates in comparison to the cases using only an unmodified EVOH (F)(Comparative Examples 1 and 2). On the other hand, in ComparativeExample 3 using a multifunctional epoxy compound, bisphenol A diglycidylether, in place of a monofunctional epoxy compound (B) having amolecular weight of not more than 500, the aforementioned effects ofimproving flexibility, flexing resistance and stretchability were notobtained.

In comparison to the cases using only a modified EVOH (C) (ComparativeExamples 4 to 8), the resin compositions comprising an EVOH (F) and amodified EVOH (C) having a structural unit (I) (Examples 1 to 13)demonstrate greatly improved oxygen barrier properties while maintainingsuperior flexibility, superior flexing resistance and superiorstretchability which the modified EVOH (C) inherently possesses. On theother hand, in the cases using the resin compositions containing an EVOH(F) and an EVOH of a low degree of saponification (Comparative Examples9 to 11), the aforementioned effects of improving flexibility, flexingresistance and stretchability were not obtained.

EXAMPLE 14

“UE320” manufactured by Japan Polychem Co., Ltd. (MFR=0.7 g/10 min at190° C. under a load of 2160 g) was used as a linear low densitypolyethylene (LLDPE), “Admer NF500” manufactured by Mitsui Chemicals,Inc. (MFR=1.8 g/10 min at 230° C.-2160 g) was used as an adhesive resin,and the resin composition prepared in Example 1 was used as a barriermaterial. A three-kind five-layer parison having a layer constitution,LLDPE/adhesive resin/barrier material/adhesive resin/LLDPE, was extrudedby use of a blow molding machine TB-ST-6P manufactured by SuzukiSeiko-sho, Co., Ltd. while setting extrusion temperature for each resinand die temperature to 210° C. The parison was blown in a mold at 15° C.and cooled for 20 seconds, yielding a 500-mL bottle comprising amultilayer blow molded article. The bottle had a total layer thicknessof 500 μm and a layer constitution: (inside) LLDPE/adhesiveresin/barrier material/adhesive resin/LLDPE (outside)=210/20/30/20/220μm. The bottle was able to be molded without any special problems. Inaddition, the bottle had a good appearance.

EXAMPLE 15

A multilayer film (nylon 6 resin/barrier material/adhesive resin/LLDPEresin) was produced under the conditions shown below by use of afour-kind four-layer coextrusion machine using the resin compositionprepared in Example 11 as a barrier material. The constitution of thefilm comprises 10 μm of the nylon 6 resin (“Ube nylon 1022B”manufactured by Ube Industries, Ltd.), 20 μm of the barrier material, 10μm of the adhesive resin (“Admer NF500” manufactured by MitsuiChemicals, Inc.) and 60 μm of the LLDPE resin (“ULTZEX 3520L”manufactured by Mitsui Chemicals, Inc.)

The coextrusion molding conditions are as follows.

Layer Constitution:

-   nylon 6 resin/barrier material/adhesive resin/LLDPE resin (thickness    10/20/10/60 in μm)    Extrusion Temperature of Nylon 6 Resin:-   C1/C2/C3/C4=230/240/250/250° C.    Extrusion Temperature of Adhesive Resin:-   C1/C2/C3=170/170/220/220° C.    Extrusion Temperature of Barrier Material:-   C1/C2/C3/C4=175/210/230/230° C.    Extrusion Temperature of LLDPE Resin:-   C1/C2/C3=170/170/220/220° C.-   Temperature of adapter: 250° C.-   Temperature of die: 250° C.    Specifications of Extruder for Each Resin and T-Die:    Nylon 6 Resin:-   40φ extruder, model UT-40-H (manufactured by Research Laboratory Of    Plastics Technology Co., Ltd.)    Adhesive Resin:-   40φ extruder, model 10VSE-40-22 (manufactured by Osaka Seiki Co.,    Ltd.)    Barrier Material:-   40φ extruder, model VSVE-40-24 (manufactured by Osaka Seiki Co.,    Ltd.)    LLDPE Resin:-   65φ extruder, model 20VS-65-22 (manufactured by Osaka Seiki Co.,    Ltd.)    T-Die:-   for 650 mm-wide four-kind four-layer extrusion (manufactured by    Research Laboratory Of Plastics Technology Co., Ltd.)-   Temperature of cooling roll: 30° C.-   Drawing speed: 8 m/min

A thermoformed container was obtained by thermoforming the resultingmultilayer film so that the LLDPE resin may come to the inner layer sideof the container by use of a thermoforming machine (R530 manufactured byMultivac Inc.). Specifically, a thermoformed container was obtained byheating the multilayer film at a mold temperature of 100° C. for 2seconds and thermoforming it into a shape of the mold (rectangular solid130 mm long, 110 mm wide and 60 mm deep) by use of compressed air(pressure: 5 kgf/cm²). The appearance of the thermo formed containerobtained was observed visually. The container was stretched uniformlywithout any unevenness or local thickness deviation. Moreover, it hadgood transparency and also had good appearance.

EXAMPLE 16

A multilayer sheet (polypropylene resin/adhesive resin/barriermaterial/adhesive resin/polypropylene resin) was produced by use of athree-kind five-layer coextrusion machine using the resin compositionprepared in Example 10 as a barrier material. The constitution of thefilm comprises 420 μm of the polypropylene resin (“IdemitsuPolypropylene E-203G” made by Idemitsu Petrochemical Co., Ltd.) of theinner and outer layers, 40 μm of the adhesive resin (“Admer QF551”manufactured by Mitsui Chemicals, Inc.) and 80 μm of the barriermaterial of the middle layer.

A thermoformed container was obtained by thermoforming the resultingmultilayer sheet by use of a thermoforming machine (a vacuum-pressuredeep drawing molding machine, model FX-0431-3 manufactured by AsanoLaboratories Co., Ltd.) into a shape of a round cup (mold shape: upperpart 75 mmφ, lower part 60 mmφ, depth 75 mm, drawn ratio S=1.0) at asheet temperature of 160° C. using compressed air (pressure: 5 kgf/cm²).The molding conditions are as follows.

-   Temperature of heater: 400° C.-   Plug: 45φ×65 mm-   Temperature of plug: 150° C.-   Temperature of mold: 70° C.

The appearance of the cup-shaped thermoformed container obtained wasobserved visually. The container was stretched uniformly without anyunevenness or local thickness deviation. Moreover, it had goodtransparency and also had good appearance.

EXAMPLE 17

A multilayer film (polystyrene resin/adhesive resin/barriermaterial/adhesive resin/polystyrene resin) was produced under theconditions shown below by use of a three-kind five-layer coextrusionmachine using the resin composition prepared in Example 7 as a barriermaterial. The constitution of the film comprises 425 μm of thepolystyrene resin (“Idemitsu Polystyrol ET-61” manufactured by IdemitsuPetrochemical Co., Ltd.) of the inner and outer layers, 50 μm of theadhesive resin (“Melthene M-5420” manufactured by Tosoh Corp.) each and50 μm of the barrier material of the middle layer.

A thermoformed container was obtained by thermoforming the resultingmultilayer sheet by use of a thermoforming machine (a vacuum-pressuredeep drawing molding machine, model FX-0431-3 manufactured by AsanoLaboratories Co., Ltd.) into a shape of a round cup (mold shape: upperpart 75 mmφ, lower part 60 mmφ, depth 75 mm, drawn ratio S=1.0) at asheet temperature of 150° C. using compressed air (pressure: 5 kgf/cm²).The molding conditions are as follows.

-   Temperature of heater: 400° C.-   Plug: 45φ×65 mm-   Temperature of plug: 120° C.-   Temperature of mold: 70° C.

The appearance of the thermoformed container obtained was observedvisually. The container had no cracks, no unevenness and no localthickness deviation and was stretched uniformly. Moreover, it had goodtransparency and also had good appearance.

EXAMPLE 18

The resin composition prepared in Example 11 was used as a barriermaterial, a maleic anhydride-modified polyethylene (“Admer NF500”manufactured by Mitsui Chemicals, Inc.) was used as an adhesive resinand a water crosslinking polyethylene (“Mordakes S-141” manufactured bySumitomo Bakelite Co., Ltd.) was used as a crosslinkable polyolefin.Each of the above-mentioned resins was supplied to a coextrusion moldingmachine (“M50/28D” manufactured by Leonard Co.) for multilayer pipeproduction to produce a multilayer pipe with an outer diameter of 20 mmcomprising (outer layer) barrier material/adhesive resinlayer/crosslinkable polyolefin (inner layer). The thicknesses of theouter layer, the adhesive resin layer and the inner layer in themultilayer pipe obtained were 100 μm, 50 μm and 1850 μm, respectively.The inner layer of the resulting multilayer pipe was water-crosslinkedby passing water vapor (temperature 150° C.; pressure 4 kg/cm²) throughthe multilayer pipe for 3 minutes. Then the oxygen barrier property ofthis multilayer pipe was measured by a method described below. Theoxygen barrier property was evaluated based on the increasing speed ofdissolved oxygen. The smaller the increasing speed of dissolved oxygen,the better the oxygen barrier property.

By circulating water from which dissolved oxygen had been removed by useof a packed tower containing metallic tin through the resulting pipe,the increasing speed of the dissolved oxygen in the water at 70° C. wasmeasured under conditions: 20° C. and 65% RH. The increasing speedμg/liter·hr used herein indicates that the dissolved oxygen increases ata rate of μg/hr per liter of water in the pipe. In other words, when V1cc represents the volume of the water in the whole apparatus includingthe pipe, V2 cc represents the volume of the water in the pipe and Bμg/liter·hr represents the increase per unit time in the oxygenconcentration in the water circulated in the apparatus, theabove-mentioned increasing speed of dissolved oxygen (A μg/liter·hr) isa value calculated from A=B (V1/V2). The multilayer pipe had anincreasing speed of dissolved oxygen of 5 μg/liter·hr, showing goodoxygen barrier property.

EXAMPLE 19

A polyester based thermoplastic polyurethane (“Kuramilon U-2190”manufactured by Kuraray Co., Ltd.) was used as a thermoplasticpolyurethane elastomer, the resin composition prepared in Example 11 wasused as a barrier material, and a resin composition comprising 70 partsby weight of an ethylene-vinyl acetate copolymer (“Evaflex EV-460”manufactured by Du Pont-Mitsui Polychemicals Co., Ltd.) and 30 parts byweight of a maleic anhydride-modified ethylene-vinyl acetate copolymerbased adhesive resin (“Admer VF500” manufactured by Mitsui Chemicals,Inc.) was used as a sealant layer.

Using the resins and resin composition described above, coextrusion wascarried out under the conditions shown below to yield a multilayer filmhaving a layer constitution, thermoplastic polyurethane elastomer (50μm)/barrier material (10 μm)/sealant material (30 μm).

The coextrusion molding conditions are as follows.

Layer Constitution:

-   Thermoplastic polyurethane elastomer/barrier material/sealant layer    (thickness 50/10/30 in μm)    Extrusion Temperature of Thermoplastic Polyurethane Elastomer:-   C1/C2/C3=195/200/200° C.    Extrusion Temperature of Barrier Material:-   C1/C2/C3=175/210/210° C.    Extrusion Temperature of Sealant Material:-   C1/C2/C3=150/200/210° C.-   Temperature of die: 210° C.    Specifications of Extruder for Each Resin and T-Die:    Thermoplastic Polyurethane Elastomer:-   20φ extruder for laboratory use, ME type CO-EXT (manufactured by    Toyo Seiki Seisaku-Sho, Ltd.)    Barrier Material:-   25φ extruder, model P25-18AC (manufactured by Osaka Seiki Co., Ltd.)    Sealant Material:-   32φ extruder, model GT-32-A (manufactured by RESEARCH LABORATORY OF    PLASTICS TECHNOLOGY CO., LTD.)    T-Die:-   for 300 mm-wide three-kind three-layer extrusion (manufactured by    RESEARCH LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.)-   Temperature of cooling roll: 50° C.-   Drawing speed: 4 m/min

The multilayer film prepared above was moisture conditioned at 20° C.and 65% RH for 5 days. For the above-mentioned two moisture-conditionedsamples, oxygen transmission rates were measured using an apparatus,MOCON OX-TRAN 2/20, manufactured by Modern Control, Inc. according toJIS K7126 (Equal Pressure Method) under a 20° C.-65% RH condition andthe average thereof was calculated. The oxygen transmission rate of themultilayer film of this Example was 0.8 cc/m²·day·atm.

Then, using the multilayer film, the skin packaging aptitude wasevaluated. On a two-layer film, as a lid material 4, which comprised a100-μm thick polyethylene terephthalate film (“Lumirror #100”manufactured by Toray Industries, Inc.) and a 40-μm thick ethylene-vinylacetate copolymer film (“Lamilon SR-L10” manufactured by Sekisui FilmNishinippon Co., Ltd.) laminated together by dry lamination, a content(sliced ham) 5 was placed while the ethylene-vinyl acetate copolymerlayer was faced with the sliced ham. Then, the film for evaluation wassubjected to skin packaging using a skin packaging test machine (avacuum-pressure deep drawing molding machine, model FX-0431-3,manufactured by Asano Laboratories Co., Ltd.) (see FIG. 9).

The film was preheated with a preheater 1 set at 100° C. Then theaforementioned multilayer film 3 was vacuum formed by means of an uppermold 2 (temperature controlling device) kept at 90° C. Subsequently, theupper mold 2 and a lower mold 7 were mated together and then the insideof the molds was brought into vacuum by degassing through vacuumingtubes 8 and 9. After the inside of the molds reached vacuum, a heatsealer 6 mounted on a heat sealer base 10 was actuated to heat seal incircular shape around the sliced ham. Then the inside of the mold wasbrought back to the atmospheric pressure, yielding a skin package inwhich the film for evaluation was shaped in tight contact with thesurface of the content, sliced ham.

For the formed skin package, the appearance of the package was evaluatedwith respect to two points, follow ability to the shape of the content(degree of deformation of the content) and a state of the wrinkleformed. As a result, in the skin package comprising the multilayer filmof this Example, there was almost no change in the shape of the contentand the film followed the shape of the content well. In addition, nowrinkles were formed and, therefore, good contactibility was shown.

EXAMPLE 20

The resin composition prepared in Example 11 was used as a barriermaterial, “Eveflex EV-340” manufactured by Du Pont-Mitsui PolychemicalsCo., Ltd. was used as an EVA resin, and “Admer VF-600” manufactured byMitsui Chemicals, Inc. was used as an adhesive resin. Using theabove-mentioned resins, a multilayer sheet having a layer constitution,EVA resin/adhesive resin/barrier material/adhesive resin/EVA resin(=300/50/50/50/300 μm), was produced under the following conditions byuse of a three-kind five-layer coextrusion machine.

The coextrusion molding conditions are as follows.

Layer Constitution:

-   EVA resin/adhesive resin/barrier material/adhesive resin/EVA resin-   (thickness 300/50/50/50/300 in μm)    Extrusion Temperature of Each Resin:-   C1/C2/C3/die=170/170/220/220° C.    Specifications of Extruder for Each Resin and T-Die:    EVA Resin:-   32φ extruder, model GT-32-A (manufactured by RESEARCH LABORATORY OF    PLASTICS TECHNOLOGY CO., LTD.)    Adhesive Resin:-   25φ extruder, model P25-18AC (manufactured by Osaka Seiki Co., Ltd.)    Barrier Material:-   20φ extruder for laboratory use, ME type CO-EXT (manufactured by    Toyo Seiki Seisaku-Sho, Ltd.)    T-Die:-   for 300 mm-wide 3-kind 5-layer extrusion (manufactured by RESEARCH    LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.)-   Temperature of cooling roll: 50° C.-   Drawing speed: 4 m/min

The multilayer sheet prepared above was put in a pantograph type biaxialstretching machine manufactured by Toyo Seiki Seisaku-Sho, Ltd. and wassubjected to simultaneous biaxial stretching at a draw ratio of 3×3 at70° C. to obtain a multilayer oriented film. The multilayer sheetmentioned above showed good stretchability. After the drawing, themultilayer oriented film had few cracks, little unevenness and littlelocal thickness deviation and, therefore, had a good appearance(transparency, gels and pimples).

The multilayer oriented film prepared above was moisture conditioned at20° C.-100% RH for 5 days. For the above-mentioned twomoisture-conditioned samples, oxygen transmission rates were measuredusing an apparatus, MOCON OX-TRAN 2/20, manufactured by Modern Control,Inc. according to JIS K7126 (Equal Pressure Method) under a 20° C.-100%RH condition and the average thereof was calculated. The oxygentransmission rate of the multilayer oriented film of this Example was1.3 cc/m²·day·atm and a good gas barrier property was shown.

Moreover, the heat shrinkability obtained when the multilayer orientedfilm prepared above is used as a heat shrinkable film was evaluatedaccording the method described below. Specifically, the above multilayeroriented film was immersed in hot water at 90° C. for one minute, andthe area shrinkage percentage was determined. The multilayer orientedfilm of this Example had an area shrinkage percentage of 57% and,therefore, showed a good heat shrinkability.

EXAMPLE 21

A thermoplastic polyester resin was produced according to the methodmentioned below.

A slurry comprising 100.000 parts by weight of terephthalic acid and44.830 parts by weight of ethylene glycol was prepared and 0.010 part byweight of germanium dioxide, 0.010 part by weight of phosphorous acidand 0.010 part by weight of tetraethyl ammonium hydroxide were addedthereto. The resulting slurry was heated under pressure (absolutepressure of 2.5 Kg/cm²) at 250° C. for esterification to a degree ofesterification up to 95%, thereby giving an oligomer. The resultingoligomer was subjected to melt polycondensation under a reduced pressureof 1 mmHg at a temperature of 270° C. to obtain a polyester having anintrinsic viscosity of 0.50 dl/g. The resulting polyester was extrudedthrough a nozzle into a strand, cooled with water, and pelletized intocolumnar pellets (diameter: about 2.5 mm, length: about 2.5 mm). Theresulting pellets were pre-dried at 160° C. for 5 hours andcrystallized. Thus was obtained a polyester prepolymer.

The structural unit contents of the resulting polyester prepolymer weremeasured by NMR. The terephthalic acid unit content, the ethylene glycolunit content and the content of diethylene glycol unit by-produced inthe polyester were 50.0 mol %, 48.9 mol % and 1.1 mol %, respectively.The terminal carboxyl group concentration and the melting point of thepolyester were measured according to the methods mentioned hereinaboveto be 38 μeq/g and 253° C., respectively. The resulting polyesterprepolymer were pre-dried at 160° C. for 5 hours and crystallized.

The crystallized polyester prepolymer was subjected to solid-phasepolymerization in a rotary vacuum solid-phase polymerization device,under a reduced pressure of 0.1 mmHg at 220° C. for 10 hours, into athermoplastic polyester resin having an increased molecular weight. Thecharacteristic values of the thermoplastic polyester resin obtained weremeasured according to the methods mentioned below.

(1) Structural Unit Contents in Polyester:

The content of each structural unit in a polyester was determined from a¹H-NMR (nuclear magnetic resonance) spectrum (measured by “JNM-GX-500”manufactured by JEOL Ltd.) of the polyester using deuteratedtrifluoroacetic acid as a solvent.

(2) Intrinsic Viscosity of Polyester:

A sample was taken out of the polyester layer of the body part of amultilayer container, and its intrinsic viscosity was measured in anequiweight mixed solvent of phenol and tetrachloroethane, at 30° C.using an Ubbelohed's viscometer (model “HRK-3” manufactured by HayashiSeisakusho Co. Ltd.).

(3) Glass Transition Temperature and Melting Point of Polyester:

A sample is taken out of the polyester layer of the body part of amultilayer container, and its glass transition temperature and meltingpoint were measured by differential scanning calorimetry (DSC) accordingto JIS K7121 using a differential scanning calorimeter (DSC) of modelRDC220/SSC5200H manufactured by Seiko Instruments & Electronics Ltd.Precisely, in the device, the sample was kept at 280° C. for 5 minutes,then cooled to 30° C. at a cooling rate of 100° C./min, kept at thetemperature for 5 minutes, and then heated at a heating rate of 10°C./min. For temperature calibration, used are indium and lead. The glasstransition temperature as referred to herein indicates the midway glasstransition temperature (Tmg) according to JIS K7121, and the meltingpoint also referred to herein indicates the peak point in melting (Tpm)according to the same.

The contents of terephthalic acid unit, ethylene glycol unit anddiethylene glycol unit in the thermoplastic polyester resin obtainedwere 50.0 mol %, 48.9 mol % and 1.1 mol %, respectively. The intrinsicviscosity, the melting point and the glass transition temperature were0.83 dl/g, 252° C. and 80° C., respectively.

Using the resin composition prepared in Example 1 and the thermoplasticpolyester (PES) prepared by the method described above, obtained was atwo-kind three-layer parison of PES/resin composition/PES, throughcoinjection molding using a coinjection molding machine (model SL160,four cavities) manufactured by KORTEC/HUSKY. Concretely, the temperatureof the PES injection zone was 280° C.; the temperature of the resincomposition injection zone was 210° C.; the temperature of the hotrunner block in which the PES and the resin composition were combinedwas 270° C.; the temperature of the injection mold core was 10° C.; andthe temperature of the injection mold cavity was 10° C. When the parisonwas observed visually, no streaks were found and, therefore, the leadingedge of the resin composition layer in the opening of the parison was ina good condition.

Thereafter, stretch blow molding was carried out by heating the parisonto 105° C. at a surface temperature using a stretch blow molding machine(model LB01, one 530-mL cavity) manufactured by Crupp CorpoplastMaschinenbau, to give a two-kind three-layer type multilayer coinjectionblow molded container. When the blow molded container was observedvisually, neither streaks, bubbles nor gels were found and, therefore,the container had a good appearance. Using the multilayer blow moldedcontainer obtained, the incidence of delamination in the container, thehaze of the container body and the oxygen transmission rate of thecontainer were measured by the methods shown below.

(1) Incidence of Delamination in Multilayer Container:

100 molded bottles each are filled with water as a content andhermetically sealed with a stopper under normal pressure. Each bottlewith its body being kept horizontally was spontaneously dropped from aheight of 60 cm onto a triangular stand having a length of 20 cm andhaving an angle of 90° at its edge that faces the dropping bottle. Thedropping test was effected only once, in which the edge of the stand istargeted to the center of the body of the bottle. From the number of thebottles in which delamination occurred, the incidence of delaminationwas calculated according to the following equation:Incidence of delamination=[(number of bottles in which delaminationoccurred)/100]×100 (%)(2) Haze of Multilayer Container:

The body of a bottle obtained was divided into four equal portionsaround the circumference at its center, and the internal haze of each ofthose four portions was measured with a Poic integrating-sphere lighttransmittance/complete light reflectance meter (HR-100 Model fromMurakami Color Technology Laboratories) according to ASTM D1003-61. Thedata were averaged and the resulting mean value indicated the haze ofthe bottle.

(3) Oxygen Transmission Rate of Multilayer Container:

A bottle obtained was conditioned at 20° C. and 65% RH, and the oxygentransmission rate per one bottle (cc/container·day·atm) was measuredusing an oxygen transmission rate meter (OX-TRAN-10/50A manufactured byModern Control, Inc.).

The above-mentioned evaluation results are summarized in Table 4. Inaddition, when the appearance of a container produced by stretch blowmolding this parison was observed, neither streaks, bubbles nor gelswere found and, therefore, the container had a good appearance.

EXAMPLE 22

Evaluation was carried out in the same manner as Example 21 except usingthe resin composition prepared in Example 4 as a resin composition. Theresults are shown in Table 4.

EXAMPLE 23

Evaluation was carried out in the same manner as Example 21 except usingthe resin composition prepared in Example 5 as a resin composition. Theresults are shown in Table 4.

EXAMPLE 24

Evaluation was carried out in the same manner as Example 21 except usingthe resin composition prepared in Example 11 as a resin composition. Theresults are shown in Table 4.

EXAMPLE 25

Evaluation was carried out in the same manner as Example 21 except usingthe resin composition prepared in Example 12 as a resin composition. Theresults are shown in Table 4.

COMPARATIVE EXAMPLE 12

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using only the EVOH (F) used in Example 1 inplace of the resin composition. The results are shown in Table 4.

COMPARATIVE EXAMPLE 13

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using only the EVOH (F) used in Example 5 inplace of the resin composition. The results are shown in Table 4.

COMPARATIVE EXAMPLE 14

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using only the modified EVOH (C) obtained inSynthesis Example 1 in place of the resin composition. The results areshown in Table 4.

COMPARATIVE EXAMPLE 15

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using the composition used in ComparativeExample 9 in place of the resin composition. The results are shown inTable 4.

COMPARATIVE EXAMPLE 16

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using the composition used in ComparativeExample 10 in place of the resin composition. The results are shown inTable 4.

COMPARATIVE EXAMPLE 17

The evaluations of the moldability of a parison, the incidence ofdelamination of a container, the haze of the body of a container and theoxygen transmission rate of the container were conducted in the samemanner as Example 21 except using the composition used in ComparativeExample 11 in place of the resin composition. The results are shown inTable 4.

TABLE 4 Resin composition or EVOH constituting the middle layer ModifiedEVOH (C) Evaluation results Structural EVOH (F) Oxygen unit (I) EthyleneEthylene Weight Moldability Incidence of transmission Epoxy compoundcontent content content ratio of parison delamination Haze rate (B) (mol%) (mol %) (mol %) (C.)/(F.) *1) (%) (%) *2) Example 21 1,2-Epoxybutane4.8 32 32 20/80 ◯ 8 2.1 0.012 Example 22 Epoxypropane 5.5 32 32 50/50 ◯6 2.0 0.014 Example 23 Epoxypropane 5.5 32 44 20/80 ◯ 9 2.6 0.017Example 24 Epoxypropane 8 44 32 *3) 20/80 ◯ 7 2.7 0.014 Example 25Glycidol 5 32 32 20/80 ◯ 6 2.0 0.013 Comparative — — — 32  0/100 X 952.5 0.011 Example 12 Comparative — — — 44  0/100 X 85 2.9 0.019 Example13 Comparative 1,2-Epoxybutane 4.8 32 — 100/0  ◯ 5 2.7 0.019 Example 14Comparative EVOH with low degree of 32 32 20/80 ◯ 78 2.7 0.015 Example15 saponification Comparative EVOH with low degree of 32 32 50/50 ◯ 532.6 0.021 Example 16 saponification Comparative EVOH with low degree of44 32 20/80 ◯ 77 3.2 0.018 Example 17 saponification *1) ◯: A parisonafter molding had a leading edge of good conditions. X: A parison aftermolding had a leading edge of bad conditions. *2) Unit: cc/container ·day · atm *3) Boric acid treatment

As shown in Examples 21-25, the coinjection stretch blow moldedcontainers using resin compositions of the present invention aresuperior in moldability of a parison, delamination resistance,transparency and oxygen gas barrier property. In contrast to this,Comparative Examples 12 and 13, in which only an unmodified EVOH (F) wasused, the moldability of a parison and delamination resistance are verypoor. In Comparative Example 14 where only a modified EVOH (C) was used,the oxygen transmission rate increases though the delaminationresistance is good. Furthermore, in Comparative Examples 15 to 17 wherean EVOH of a low degree of saponification was incorporated, theincidence of delamination and the oxygen transmission rate increase.

In other words, the coinjection stretch blow molded container of thepresent invention can prevent delamination caused by impact withouthaving an adhesive resin layer and it is superior in transparency andgas barrier properties. The containers are suitable for preservingvarious contents therein in good condition for a long period of time,and are especially useful as those for various beverages such ascarbonated beverages, beer, wine and others, and also for variousedibles or cosmetics.

EXAMPLE 26

30 parts by weight of the modified EVOH (C) used in Synthesis Example 1as modified EVOH (C) and 70 parts by weight of a linear low densitypolyethylene (Ultozex 2022L manufactured by Mitsui Chemicals, Inc.) aspolyolefin (G) were dry blended. Using a 30 mmφ twin screw extruder(TEX-30SS-30CRW-2V manufactured by The Japan Steel Works, LTD.), theblend was extruded into pellets at an extrusion temperature of 210° C.under conditions: a screw rotation speed of 400 rpm and an extrusionresin amount of 25 kg/hr. Then hot air drying was carried out at 80° C.for 16 hour, yielding a resin composition.

Subsequently, the resin composition pellets were fed to a injectionmolding machine equipped with a mold for forming a molded article shownin FIG. 12. Then, a pouring opening with a pull ring coupled to a capwith a hinge was formed by injection molding. At that time, theinjection molding machine was set to a cylinder temperature of 230° C.and a nozzle temperature of 220° C.

The thus-formed pouring opening with a pull ring was cut partly into asmall piece. The modified EVOH (C) in the cut surface of the small piecewas stained with iodine and the cut surface of the small piece wasobserved through an optical microscope. Thus, it was determined whetherthe modified EVOH (C) forms a continuous phase or a dispersed phase. Thecontinuous phase was the linear low density polyethylene, whereas themodified EVOH (C) was present as a dispersed phase. Evaluation of thepouring opening with a pull ring was conducted in the manner describedbelow. The components and the like of the resin composition and theevaluation results and the like of the molded article are summarized inTable 5 and Table 6, respectively.

(1) Barrier Property (Oxygen Transmission Rate)

The resin composition was melt extruded through a T-die at 240° C. toform a film 100 μm thick, which was then moisture conditioned underconditions: a temperature of 20° C. and 65% RH for 2 weeks and wasdetermined for oxygen transmission rate (cc·20 μm/m²·day·atm) accordingto JIS K7126 at a temperature of 20° C. at 65% RH using an oxygentransmission tester, Ox-Tran 10/50 Model (manufactured by Modern ControlInc., U.S.A.).

(2) Cap Strength

The molded pouring opening with a pull ring was moisture conditionedunder conditions: a temperature of 20° C. and 65% RH for 2 weeks. Then,it was dropped five times from a height of 5 m and was checked fordamage. The cap strength was determined according to the criteria shownbelow.

Criteria:

-   ⊚: No deformation was found after 5 droppings.-   ◯: No deformation was found after 3 droppings, but cracks or damage    was formed by 5 droppings.-   Δ: No deformation was found after 1 dropping, but cracks or damage    was found by 2 droppings.-   X: Cracks or damage was formed by 2 droppings.    (3) Easy Openability

100 pouring openings with a pull ring were opened by pulling the pullring with fingers. The condition of a thin portion cut by the forceapplied during the opening was judged according to the criteria shownbelow.

Criteria:

-   ⊚: The thin portion was cut and it is easy to open.-   ◯: It is relatively easy to open.-   X: It is difficult to open. The thin portion cannot be cut.    (4) Pull Ring Strength

100 pouring openings with a pull ring were opened by pulling the pullring with fingers. They were evaluated whether they can be opened easilywithout causing breakage in their rings during the opening. The pullring strength was determined according to the criteria shown below.

Criteria:

-   ⊚: The number of pull rings broken is up to 10.-   ◯: The number of pull rings broken is more than 10 but not more than    30.-   Δ: The number of pull rings broken is more than 30 but not more than    50.-   X: The number of pull rings broken is more than 50.    (5) Hinge Strength

100 pouring openings with a pull ring were moisture conditioned underconditions: a temperature of 20° C. and 65% RH. Then, their caps wereopened and closed repeatedly 200 times. The strength of the hinge wasdetermined according to the criteria shown below.

Criteria:

-   ⊚: The number of pouring openings the hinges of which were broken is    up to 10.-   ◯: The number of pouring openings the hinges of which were broken is    more than 10 but not more than 30.-   Δ: The number of pouring openings the hinges of which were broken is    more than 30 but not more than 50.-   X: The number of pouring openings the hinges of which were broken is    more than 50.    (6) Recyclability

Flashes formed in the injection molding of pouring openings with a pullring, such as those formed at a liner portion, were crushed, fed againto an injection molding machine, and molded again into pouring openingwith a pull ring under the same conditions as mentioned previously. Themolded articles were evaluated for the above-described items except theevaluation of barrier property.

EXAMPLE 27

30 parts by weight of the modified EVOH (C) obtained in SynthesisExample 3 as modified EVOH (C), 65 parts by weight of a linear lowdensity polyethylene (Ultozex 2022L manufactured by Mitsui Chemicals,Inc.) as polyolefin (G) and 5 parts by weight a metal salt of anethylene-methacrylic acid random copolymer (content of methacrylic acidin the copolymer: 7.5 mol %, counter ion: Zn, neutralization degree:40%, melt flow rate (at 190° C. under a load of 2160 g): 1.1 g/10 min)as compatibilizer (H) were dry blended. Using a 30 mmφ twin screwextruder (TEX-30SS-30CRW-2V manufactured by The Japan Steel Works,LTD.), the blend was extruded into pellets at an extrusion temperatureof 210° C. under conditions: a screw rotation speed of 400 rpm and anextrusion resin amount of 25 kg/hr. Then, hot air drying was carried outat 80° C. for 16 hour, yielding a resin composition. Using the resultingresin composition, evaluations were conducted in the same manner asExample 26. The components and the like of the resin composition and theevaluation results and the like of the molded article are summarized inTable 5 and Table 6, respectively.

EXAMPLE 28

20 parts by weight of the EVOH (F) used in Example 5 and 15 parts byweight of the modified EVOH (C) obtained in Synthesis Example 4 were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hour,yielding a resin composition composed of EVOH (F) and modified EVOH (C).Subsequently, 35 parts by weight of the resulting resin compositioncomposed of EVOH (F) and modified EVOH (C) and 65 parts by weight of alinear low density polyethylene (Ultozex 2022L manufactured by MitsuiChemicals, Inc.) as polyolefin (G) were dry blended. Using a 30 mmφ twinscrew extruder (TEX-30SS-30CRW-2V manufactured by The Japan Steel Works,LTD.), the blend was extruded into pellets at an extrusion temperatureof 210° C. under conditions: a screw rotation speed of 400 rpm and anextrusion resin amount of 25 kg/hr. Then, hot air drying was carried outat 80° C. for 16 hour, yielding a resin composition. Using the resultingresin composition, evaluations were conducted in the same manner asExample 26. The components and the like of the resin composition and theevaluation results and the like of the molded article are summarized inTable 5 and Table 6, respectively.

EXAMPLE 29

20 parts by weight of the EVOH (F) used in Example 1 and 15 parts byweight of the modified EVOH (C) obtained in Synthesis Example 4 were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hour,yielding a resin composition composed of EVOH (F) and modified EVOH (C).Subsequently, 35 parts by weight of the resulting resin compositioncomposed of EVOH (F) and modified EVOH (C), 60 parts by weight of alinear low density polyethylene (Ultozex 2022L manufactured by MitsuiChemicals, Inc.) as polyolefin (G) and 5 parts by weight of a materialprepared in the manner described below as compatibilizer (H) were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 210° C. under conditions: ascrew rotation speed of 400 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hour,yielding a resin composition.

Production Method of Compatibilizer (H):

To a 37φ twin screw extruder including a resin feeder (the inlet sectionof the extruder), a liquid feeder (the middle section of the extruder)and vents (provided at two points, before the liquid feeder and beforethe outlet of the extruder), an ultra low density polyethylene(“Excellen” (commercial name) EUL430 manufactured by Sumitomo ChemicalCo., Ltd.) (melt index (MI): 4 g/10 min (at 190° C. under a load of 2160g), amount of double bond: 4.7×10⁻² meq/g, density: 0.89 g/cm³) was fedat a rate of 8 kg/hr. On the other hand, from the liquid feeder, a mixedsolution of triethylamine borane and boric acid 1,3-butanediol esterwith a weight ratio of 29:71 was added at a rate of 0.2 kg/hr (0.058kg/hr for triethylamine borane and 0.142 kg/hr for boric acid1,3-butanediolester). Thus, an ultra low density polyethylene with amelt index (MI) of 4 g/10 min (at 190° C. under a load of 2160 g) wasobtained which had on its terminal 0.03 meq/g of boric acid1,3-butanediol ester group. This ultra low density polyethylene with aboric acid 1,3-butanediol ester group was used as compatibilizer (H).

Extruder:

-   TEM-35B (Toshiba Machine Co., Ltd.)-   D=37 mm, L/D=53.8-   Position of liquid feeder: C8-   Position of vent: C6 and C14-   Temperature setting-   C1-C6: 240° C.-   C7-C15: 260° C.-   Die: 250° C.-   Screw rotation speed: 100 rpm

Using the resulting resin composition, evaluations were conducted in thesame manner as Example 26. The components and the like of the resincomposition and the evaluation results and the like of the moldedarticle are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 18

Using only the linear low density polyethylene (Ultozex 2022Lmanufactured by Mitsui Chemicals, Inc.) used in Example 26, evaluationswere conducted in the same manner as Example 26. The components and thelike of the resin composition and the evaluation results and the like ofthe molded article are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 19

Using only the EVOH (F) used in Example 5, evaluations were conducted inthe same manner as Example 26. The components and the like of the resincomposition and the evaluation results and the like of the moldedarticle are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 20

Using 30 parts by weight of the EVOH (F) used in Example 1 and 70 partsby weight of a linear low density polyethylene (Ultozex 2022Lmanufactured by Mitsui Chemicals, Inc.) as polyolefin (G), twin screwextrusion was conducted in the same manner as Example 26 to obtain aresin composition. Using the resulting resin composition, evaluationswere conducted in the same manner as Example 26. The components and thelike of the resin composition and the evaluation results and the like ofthe molded article are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 21

Using 30 parts by weight of the EVOH (F) used in Example 1, 65 parts byweight of a linear low density polyethylene (Ultozex 2022L manufacturedby Mitsui Chemicals, Inc.) as polyolefin (G) and 5 parts by weight ofthe compatibilizer (H) used in Example 27, twin screw extrusion wasconducted in the same manner as Example 26 to obtain a resincomposition. Using the resulting resin composition, evaluations wereconducted in the same manner as Example 26. The components and the likeof the resin composition and the evaluation results and the like of themolded article are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 22

Using 35 parts by weight of the EVOH (F) used in Example 5 and 65 partsby weight of a linear low density polyethylene (Ultozex 2022Lmanufactured by Mitsui Chemicals, Inc.) as polyolefin (G), twin screwextrusion was conducted in the same manner as Example 26 to obtain aresin composition. Using the resulting resin composition, evaluationswere conducted in the same manner as Example 26. The components and thelike of the resin composition and the evaluation results and the like ofthe molded article are summarized in Table 5 and Table 6, respectively.

COMPARATIVE EXAMPLE 23

Using 30 parts by weight of the EVOH (F) used in Example 5, 65 parts byweight of a linear low density polyethylene (Ultozex 2022L manufacturedby Mitsui Chemicals, Inc.) as polyolefin (G) and 5 parts by weight ofthe compatibilizer (H) used in Example 29, twin screw extrusion wasconducted in the same manner as Example 26 to obtain a resincomposition. Using the resulting resin composition, evaluations wereconducted in the same manner as Example 26. The components and the likeof the resin composition and the evaluation results and the like of themolded article are summarized in Table 5 and Table 6, respectively.

TABLE 5 Modified EVOH (C) Structural EVOH(F) Weight unit (I) EthyleneEthylene ratio Epoxy content content content Polyolefin Compatibilizer(C)/(F)/ Continuous compound (B) (mol %) (mol %) (mol %) (G) (H) (G)/(H)phase Comparative 1,2- 4.8 32 — LLDPE — 30/0/70/0 LLDPE Example 26Epoxybutane Comparative Epoxypropane 5.5 32 — LLDPE *1) 30/0/65/5 LLDPEExample 27 Comparative Epoxypropane 8 44 44 LLDPE — 15/20/65/0 LLDPEExample 28 Comparative Epoxypropane 8 44 32 LLDPE *2) 15/20/60/5 LLDPEExample 29 Comparative — — — — LLDPE — 0/0/100/0 LLDPE Example 18Comparative — — — 44 — — 0/100/0/0 EVOH Example 19 Comparative — — — 32LLDPE — 0/30/70/0 LLDPE Example 20 Comparative — — — 32 LLDPE *1)0/30/65/5 LLDPE Example 21 Comparative — — — 44 LLDPE — 0/35/65/0 LLDPEExample 22 Comparative — — — 44 LLDPE *2) 0/35/60/5 LLDPE Example 23 *1)Ethylene-methacrylic acid copolymer *2) Boronic acid estergroup-containing ultra low density polyethylene

TABLE 6 Oxygen transmission Easy Recyclability rate Cap open- Ring HingeCap Easy Ring Hinge *1) strength ability strength strength strengthopenability strength strength Example 26 230 ⊚ ◯ ◯ Δ ◯ ◯ ◯ Δ Example 27190 ⊚ ⊚ ⊚ ◯ ⊚ ⊚ ⊚ ◯ Example 28 250 ⊚ ◯ ◯ ⊚ ◯ ◯ ◯ ◯ Example 29 160 ⊚ ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ Comparative 4,500 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example 18 Comparative 1.5 XX X X X X X X Example 19 Comparative 90 X X X X X X X X Example 20Comparative 100 Δ X Δ X X X X X Example 21 Comparative 140 X X X X X X XX Example 22 Comparative 180 Δ X Δ X X X X X Example 23 *1) cc · 20μm/m² · day · atm

The pouring openings with a pull ring of the present invention obtainedin Examples 26 to 29 were superior in barrier property and alsodemonstrated satisfactory cap strengths in the dropping evaluation.Moreover, they are superior in easy openability and also are excellentin mechanical strengths such as ring strength and hinge strength.Comparative Example 18 where only polyolefin (G) was used resulted in anextremely poor gas barrier property. Regarding Comparative Example 19where only EVOH (F) was used, Comparative Examples 20 and 22 where EVOH(F) and polyolefin (G) were used, and Comparative Examples 21 and 23where EVOH (F) polyolefin (G) and compatibilizer (H) were used, themechanical strengths such as cap strength, ring strength and hingestrength were unsatisfactory. The easy openability and the recyclabilityas well were also poor.

EXAMPLE 30

30 parts by weight of the modified EVOH (C) obtained in SynthesisExample 3 as modified EVOH (C), 65 parts by weight of a polypropylene(Novatec PP BC03B manufactured by Japan Polychem Corp.) as polyolefin(G) and 5 parts by weight a material prepared in the manner describedbelow as compatibilizer (H) were dry blended. Using a 30 mmφ twin screwextruder (TEX-30SS-30CRW-2V manufactured by The Japan Steel Works,LTD.), the blend was extruded into pellets at an extrusion temperatureof 210° C. under conditions: a screw rotation speed of 400 rpm and anextrusion resin amount of 25 kg/hr. Then, hot air drying was carried outat 80° C. for 16 hours, yielding a resin composition.

Production Method of Compatibilizer (H):

To a reactor equipped with a stirrer, a nitrogen-introduction tube, acooling tube and a distillation column, 500 parts by weight of “TuftecH1062” manufactured by Asahi Kasei Chemicals Corp. and 1500 parts byweight of decalin were charged. After replacement with nitrogen bypressure reduction, the temperature in the reactor was set to 130° C.and the solute was dissolved by stirring. To the solution, a mixture of57.5 parts by weight of triethylamine borane and 143 parts by weight of1,3-butanediol ester were added and was stirred for five minutes. Then,the stirring was stopped and the temperature in the reactor was elevatedto 200° C. After a while from the elevation of the temperature, theentire system gelled and then the gel started to dissolve from the wallof the reactor. When it became possible to stir, stirring was resumed.Following heating the system for additional one hour after completedisappearance of the gel in the reactor, the cooling tube was switchedto the distillation column and distillation under normal pressure wasstarted. The temperature in the reactor was elevated up to 220° C. andthe distillation was continued until running out almost stopped. Aftercooling the resulting solution of polymer, the solution wasreprecipitated in 5 parts by weight of acetone. Moreover, theprecipitate was vacuum dried overnight at 120° C., resulting in ahydrogenated product of a polystyrene-polybutadiene-polystyrene triblockcopolymer having 0.22 mmol/g of boronic acid 1,3-butanediol estergroups. The triblock copolymer having boronic acid 1,3-butanediol estergroups was employed as compatibilizer (H).

Subsequently, the resin composition pellets were fed to a injectionmolding machine equipped with a mold for forming a molded article shownin FIG. 13. Then, a cap for a container was formed by injection molding.At that time, the injection molding machine was set to a cylindertemperature of 230° C. and a nozzle temperature of 220° C.

The thus-formed container cap was cut partly into a small piece. Themodified EVOH (C) in the cut surface of the small piece was stained withiodine and the cut surface of the small piece was observed through anoptical microscope. Thus, it was determined whether the modified EVOH(C) forms a continuous phase or a dispersed phase. The continuous phasewas the polypropylene, whereas the modified EVOH (C) was present as adispersed phase. Evaluation of the formed container cap was conducted inthe manner described below. The evaluation results are summarized inTable 7.

(1) Barrier Property (Oxygen Transmission Coefficient)

The resin composition was melt extruded through a T-die at 240° C. toform a film of 100 μm thick, which was then moisture conditioned underconditions: a temperature of 20° C. and 65% RH for 2 weeks and wasdetermined for its oxygen transmission rate (cc·20 μm/m²·day·atm)according to JIS K7126 at a temperature of 20° C. at 65% RH using anoxygen transmission tester, Ox-Tran 10/50 Model (manufactured by ModernControl Inc., U.S.A.).

(2) Cap Strength

The formed container cap was moisture conditioned under conditions: atemperature of 20° C. and 65% RH for a month. Then, it was dropped fivetimes from a height of 5 m and was checked for damage. The cap strengthwas determined according to the criteria shown below.

Criteria:

-   ⊚: No deformation was found after 5 droppings.-   ◯: No deformation was found after 3 droppings, but cracks or damage    was formed by 5 droppings.-   Δ: No deformation was found after 1 dropping, but cracks or damage    was found by 2 droppings.-   X: Cracks or damage was formed by 2 droppings.    (3) Recyclability

Flashes formed in the injection molding of container caps, such as thoseformed at a liner portion, were crushed, fed again to an injectionmolding machine, and molded again into container caps under the sameconditions as mentioned previously. Molded articles were evaluated forthe above-described item (2) cap strength.

EXAMPLE 31

20 parts by weight of the EVOH (F) used in Example 1 and 15 parts byweight of the modified EVOH (C) obtained in Synthesis Example 4 were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hours,yielding a resin composition composed of EVOH (F) and modified EVOH (C).

Subsequently, 35 parts by weight of the resulting resin compositioncomposed of EVOH (F) and modified EVOH (C), 60 parts by weight of apolypropylene (Novatec PP BC03B manufactured by Japan Polychem Corp.) aspolyolefin (G) and 5 parts by weight of the compatibilizer (H) used inExample 30 as compatibilizer (H) were dry blended. Using a 30 mmφ twinscrew extruder (TEX-30SS-30CRW-2V manufactured by The Japan Steel Works,LTD.), the blend was extruded into pellets at an extrusion temperatureof 210° C. under conditions: a screw rotation speed of 400 rpm and anextrusion resin amount of 25 kg/hr. Then, hot air drying was carried outat 80° C. for 16 hours, yielding a resin composition. Using theresulting resin composition, evaluations were conducted in the samemanner as Example 30. The evaluation results are summarized in Table 7.

COMPARATIVE EXAMPLE 24

Using only the polypropylene (Novatec PP BC03B manufactured by JapanPolychem Corp.) used in Example 30, evaluations were conducted in thesame manner as Example 30. The evaluation results are summarized inTable 7.

COMPARATIVE EXAMPLE 25

Using only the EVOH (F) used in Example 5, evaluations were conducted inthe same manner as Example 30. The evaluation results are summarized inTable 7.

COMPARATIVE EXAMPLE 26

Using 30 parts by weight of the EVOH (F) used in Example 1, 65 parts byweight of a polypropylene (Novatec PP BC03B manufactured by JapanPolychem Corp.) as polyolefin (G) and 5 parts by weight of thecompatibilizer (H) used in Example 30, twin screw extrusion wasconducted in the same manner as Example 30, yielding a resincomposition. Using the resulting resin composition, evaluations wereconducted in the same manner as Example 30. The evaluation results aresummarized in Table 7.

COMPARATIVE EXAMPLE 27

Using 30 parts by weight of the EVOH (F) used in Example 5, 65 parts byweight of a polypropylene (Novatec PP BC03B manufactured by JapanPolychem Corp.) as polyolefin (G) and 5 parts by weight of thecompatibilizer (H) used in Example 30, twin screw extrusion wasconducted in the same manner as Example 30, yielding a resincomposition. Using the resulting resin composition, evaluations wereconducted in the same manner as Example 30. The evaluation results aresummarized in Table 7.

TABLE 7 Modified EVOH (C) Structural EVOH (F) Weight Oxygen Epoxy unit(I) Ethylene Ethylene Compat- ratio transmission Recycled compoundcontent content content Polyolefin ibilizer (C)/(F)/ Continuous rate Capcap (B) (mol %) (mol %) (mol %) (G) (H) (G)/(H) phase *1) strengthstrength Example 30 Epoxy- 5.5 32 — PP *2) 30/0/65/5 PP 150 ⊚ ⊚ propaneExample 31 Epoxy- 8 44 32 PP *2) 15/20/60/5 PP 130 ⊚ ⊚ propaneComparative — — — — PP — 0/0/100/0 PP 2,000 ⊚ ⊚ Example 24 Comparative —— — 44 — — 0/100/0/0 EVOH 1.5 X X Example 25 Comparative — — — 32 PP *2)0/30/65/5 PP 90 Δ X Example 26 Comparative — — — 44 PP *2) 0/35/60/5 PP160 Δ X Example 27 *1) cc · 20 μm/m² · day · atm *2) Boronic acid estergroup-containing triblock copolymer

The container caps using the resin compositions of the present inventionobtained in Examples 30 and 31 were superior in barrier properties andalso demonstrated satisfactory cap strengths in the dropping evaluation.Moreover, the resin compositions demonstrated superior cap strengthseven after recycling. On the other hand, Comparative Example 24, whichcomprises only polyolefin (G), exhibited an extremely poor gas barrierproperty. In Comparative Example 25, which comprises only EVOH (F), andComparative Examples 26 and 27, which comprise EVOH (F), polyolefin (G)and compatibilizer (H), the cap strength was unsatisfactory. Moreover,the recyclability was also poor.

EXAMPLE 32

80 parts by weight of the EVOH (F) used in Example 11, 10 parts byweight of the modified EVOH (C) obtained in Synthesis Example 4 and 10parts by weight of the compatibilizer (H) used in Example 29 were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hours,yielding a resin composition. The melt flow rate (at 190° C. under aload of 2160 g) was 1.1 g/10 min.

Using the thus obtained resin composition, a monolayer film, a monolayersheet and a multilayer sheet were produced in the same manner asExample 1. These were measured for their oxygen transmission rate,carbon dioxide gas transmission rate and haze and were evaluated fortheir flexing resistance and stretchability. The evaluation results ofthe film and sheets are summarized in Table 8.

Next, using the resin composition obtained, a multilayer sheet(polypropylene resin layer/adhesive resin layer/resin compositionlayer/adhesive resin layer/polypropylene resin layer) was prepared bymeans of a three-kind five-layer coextrusion machine shown later undercoextrusion molding conditions also described later. The sheetconstitution is as follows: the layers of the polystyrene resin(“EG-7FT” manufactured by Japan Polychem Corp.), both outermost layers:425 μm each; the layers of the adhesive resin (“ADMER QF500”manufactured by Mitsui Chemicals, Inc.): 50 μm each; and the layer ofthe resin composition: 50 μm.

The coextrusion molding conditions are as follows.

Layer Constitution:

-   polypropylene resin/adhesive resin/resin composition/adhesive    resin/polypropylene resin-   (thickness 425/50/50/50/425; unit: μm)    Specifications of Extruder and Extrusion Temperature for Each Resin:    Polypropylene Resin:-   65φ extruder, model 20VSE-65-22 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=200/210/230/240/240° C.    Adhesive Resin:-   40φ extruder, model 10VSE-40-22 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=130/180/210/220/220° C.    Resin Composition:-   40φ extruder, model VSVE-40-24 (manufactured by Osaka Seiki Co.,    Ltd.)-   C1/C2/C3/C4/AD=175/210/220/220/220° C.    Specifications of T-Die:-   for 600 mm-wide three-kind five-layer extrusion (manufactured by    RESEARCH LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.)-   AD/Die=240/240° C.-   Temperature of cooling roll: 80° C.-   Drawing speed: 1.2 m/min

The resulting multilayer sheet was crushed and then was extruded intopellets at an extrusion temperature of 240° C. under conditions: a screwrotation speed of 300 rpm and an extrusion resin amount of 25 kg/hr byuse of a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2V manufactured byThe Japan Steel Works, LTD.). Then, hot air drying was carried out at80° C. for 8 hours, yielding recycled pellets.

Using the thus-obtained recycled pellets, film formation was carried outunder the extrusion conditions shown below by means of a film formingmachine composed of a 40φ extruder (PLABOR GT-40-A manufactured byRESEARCH LABORATORY OF PLASTICS TECHNOLOGY CO., LTD.) and a T-die. Thus,a monolayer film of 25 μm thick was obtained.

-   Type: Single screw extruder (non-vent type)-   L/D: 24-   Bore diameter: 40 mmφ-   Screw: Single-thread full-flight type, nitrided surface steel-   Screw rotation speed: 40 rpm-   Die: Coat hanger die of 550 mm wide-   Gap between lips: 0.3 mm    Temperatures Set for Cylinders and Die:-   C1/C2/C3/adaptor/die=200/230/240/240/240 (° C.)

Using the monolayer film prepared above, the external appearance of thefilm and the dispersion condition of EVOH were evaluated according tothe criteria shown below. Thus, the recyclability (recoverability) wasjudged. Moreover, the dispersion condition of EVOH was observed by SEMby etching a cut surface of the resulting monolayer film with amethanol/isopropanol mixed solvent (50/50 vol %).

Criteria:

-   A: The number of pimples is less than 10 pimples/100 cm² and the    diameter of dispersed particles of EVOH is approximately up to 1 μm.-   B: The number of pimples is not less than 10 pimples/100 cm² but    less than 50 pimples/100 cm² and the diameter of dispersed particles    of EVOH is approximately from 1 to 5 μm.-   C: The number of pimples is not less than 50 pimples/100 cm² but    less than 100 pimples/100 cm² and the diameter of dispersed    particles of EVOH is approximately from 5 to 10 μm.-   D: The number of pimples is not less than 100 pimples/100 cm² and    there are many dispersed particles of EVOH having diameters greater    than 10 μm.

EXAMPLE 33

80 parts by weight of the EVOH (F) used in Example 11, 10 parts byweight of the modified EVOH (C) obtained in Synthesis Example 4 and 10parts by weight of the compatibilizer (H) used in Example 30 were dryblended. Using a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2Vmanufactured by The Japan Steel Works, LTD.), the blend was extrudedinto pellets at an extrusion temperature of 200° C. under conditions: ascrew rotation speed of 300 rpm and an extrusion resin amount of 25kg/hr. Then, hot air drying was carried out at 80° C. for 16 hours,yielding a resin composition. The melt flow rate (at 190° C. under aload of 2160 g) was 1.2 g/10 min. Using the thus obtained resincomposition, a monolayer film, a monolayer sheet and a multilayer sheetwere produced in the same manner as Example 1. These were measured fortheir oxygen transmission rate, carbon dioxide gas transmission rate andhaze and were evaluated for their flexing resistance and stretchability.In addition, the evaluation of recyclability (recoverability) wasconducted in the same manner as Example 32. The evaluation results aresummarized in Table 8.

COMPARATIVE EXAMPLE 28

A monolayer film, a monolayer sheet and a multilayer sheet were producedin the same manner as Example 1 using the EVOH (F) used in Example 11 inplace of the resin composition. These were measured for their oxygentransmission rate, carbon dioxide gas transmission rate and haze andwere evaluated for their flexing resistance and stretchability. Inaddition, the evaluation of recyclability (recoverability) was conductedin the same manner as Example 32. The evaluation results are summarizedin Table 8.

TABLE 8 Maximum elongation Carbon Tensile ratio of Oxygen dioxide gasYoung's strength Tensile Flexing monlayer Stretchability transmissiontransmission modulus at yield elongation Haze resistance sheet ofmultilayer rate *1) rate *1) (kgf/mm²) (kgf/mm²) at break (%) (%) (Np1)*2) (times) sheet Recyclability Example 32 0.8 3.0 159 6.1 320 0.4 2004.25 × 4.25 A A Example 33 0.8 2.8 151 5.8 330 0.4 220 4.25 × 4.25 A AComparative 0.3 1.8 195 7.5 201 0.4 36 2.25 × 2.25 E D Example 28 *1)Unit: cc · 20 μm/m² · day · atm *2) Np1: The number of flexures untilone pinhole is formed.

As shown in Examples 32 and 33, the resin compositions of the presentinvention comprising EVOH (F), modified EVOH (C) and compatibilizer (H)have a low Young's modulus, a low tensile elongation at break and a hightensile strength at yield and demonstrate good flexing resistance,stretchability and recyclability. Regarding gas barrier properties,these resin compositions have comparable performances to unmodified EVOH(F). On the other hand, as shown in Comparative Example 27, unmodifiedEVOH (F) does not achieve sufficient flexing resistance, stretchabilityor recyclability.

The following are Examples of dynamically crosslinked resincompositions. Molded articles (specimens) were produced in the mannerdescribed below by use of pellets of the resin compositions obtained inthe following Examples and Comparative Examples. The molded articleswere measured in the manner described below for properties, namely,oxygen transmission coefficient, elastic modulus, 100% modulus, tensilestrength at break, tensile elongation at break and diameter of dispersedelastomer particles.

(1) Measurement of Oxygen Transmission Coefficient:

Pellets of the resin compositions manufactured in Examples andComparative Examples described below were compression molded into 100μm-thick sheet-like specimens while being heated by use of a compressionmolding machine. Using the specimens, measurement of oxygen transmissioncoefficient was conducted. The measurement of oxygen transmissioncoefficient was conducted under conditions: an oxygen pressure of 0.34MPa, a temperature of 35° C. and a humidity of 0% RH by use of a gaspermeability rate analyzer (“GTR-10” manufactured by Yanaco Tec Corp.)

(2) Measurement of Elastic Modulus:

Using pellets of the resin compositions produced in Examples andComparative Examples described below, the pellets were compressed moldedinto sheets of 1 mm thick while being heated by means of a compressionmolding machine. From these sheets 5 mm-wide strip-shaped specimens wereproduced. The specimens were measured for dynamic viscoelasticity undertensile loading. Thus, the elastic modulus at room temperature wasdetermined. The measurement of dynamic viscoelasticity was conducted ata frequency of 1 Hz using a viscoelasticity analyzer (“DVE-V4”manufactured by Rheology Co., Ltd.)

(3) Measurements of Tensile Strength at Break, Tensile Elongation atBreak and 100% Modulus:

Dumbbell specimens of 2 mm in thickness and 5 mm in width were preparedby molding the pellets of the resin compositions manufactured inExamples, Comparative Examples or Reference Examples shown below underconditions including a cylinder temperature of 210° C. and a moldtemperature of 40° C. using a 15-ton injection molding machine(“ROBOSHOT-α15” produced by FANUC Co., Ltd.). Using the dumbbellspecimens obtained above, the tensile strength at break, the tensileelongation at break and the 100% modulus were measured at 500 mm/min inaccordance with JIS K6301 with an AUTOGRAPH produced by ShimadzuCorporation.

(4) Measurement of Average Diameter of Dispersed Particles of Elastomer(J):

The average diameter of dispersed particles was determined by electronstaining of cut surfaces of the resin compositions manufactured inExamples and Comparative Examples shown below, followed by observationthrough a scanning electron microscope. In Table 2 below, the symbol “-”indicates that elastomer (J) forms not a dispersed phase but a matrixphase or that the elastomer (J) comprises a single phase.

The particulars of the modified EVOH (C), elastomer (J) and crosslinkingagent (K) used in Examples and Comparative Examples shown below are asfollows.

Modified EVOH (C)

Employed was the modified EVOH (C) obtained in Synthesis Example 1having an ethylene content of 32 mol % and a content of structural unit(I) of 4.8 mol %.

Elastomer (J-1)

A triblock copolymer which is made up of polystyrene block-hydrogenatedpolybutadiene block-polystyrene block and which contains maleicanhydride groups (styrene unit content=30mass %, molecularweight=100,000, acid value=5 mg CH₃ONa/g, amount of maleic anhydridegroup=6.5 groups/molecule).

Elastomer (J-2)

A triblock copolymer which is made up of polystyrene block-hydrogenatedpolybutadiene block-polystyrene block and which contains 210 μeq/g ofboronic acid 1,3-butanediol ester group (styrene unit content=30 mass %,molecular weight=100,000, amount of boronic acid 1,3-butanediol estergroup=21 groups/molecule).

Crosslinking Agent (K-1):

-   1,9-nonanediamine    Crosslinking Agent (K-2):-   Inositol

EXAMPLES 34-39

-   (1) The above-mentioned modified EVOH (C), elastomer (J) and    crosslinking agent (K) at the proportions shown in the following    Table 9 were preliminarily mixed, followed by supplying the mixture    to a twin screw extruder (“ZSK-25WLE” manufactured by Krupp Werner &    Pfleiderer), melt kneading under conditions: a cylinder temperature    of 200° C. and a screw rotation speed of 350 rpm, extruding and    cutting. Pellets of each resin composition were prepared thereby.-   (2) Using the pellets of the resin compositions prepared in (1)    above, press films and molded articles (specimens) were produced in    the methods mentioned previously. Their oxygen transmission    coefficients, elastic moduli at 20° C., tensile strengths at break,    tensile elongations at break and 100% moduli were measured by the    methods described above. The results are shown in Table 9 below.

TABLE 9 Example 34 Example 35 Example 36 Example 37 Example 38 Example39 Modified EVOH (C) 70 50 30 70 50 30 Elastomer (J-1) 30 50 70Elastomer (J-2) 30 50 70 Crosslinking agent (K-1) 0.2 0.4 0.4Crosslinking agent (K-2) 5 5 5 Oxygen transmission 12 23 155 16 30 175coefficient (ml · 20 μm/m² · day · atm) Elastic modulus (Pa) 2.4 × 10⁸9.1 × 10⁷ 3.8 × 10⁷ 2.8 × 10⁸ 9.5 × 10⁷ 3.9 × 10⁷ 100% modulus (MPa) 1812 10 19 13 10 Tensile strength at break 27 15 15 27 16 16 (MPa) Tensileelongation at break 230 365 520 215 360 475 (%) Average diameter of 8 910 10 12 12 dispersed particles (μm)

COMPARATIVE EXAMPLES 29 AND 30

-   (1) The above-mentioned modified EVOH (C) and elastomer (J) at the    proportions shown in the following Table 10 were preliminarily    mixed, followed by supplying the mixture to a twin screw extruder    (“ZSK-25WLE” manufactured by Krupp Werner & Pfleiderer) without    addition of crosslinking agent (K), melt kneading under conditions:    a cylinder temperature of 200° C. and a screw rotation speed of 350    rpm, extruding and cutting. Pellets of each resin composition were    prepared thereby.-   (2) Using the pellets of the resin compositions prepared in (1)    above, press films and molded articles (specimens) were produced in    the methods mentioned previously. Their oxygen transmission    coefficients, elastic moduli, tensile strengths at break, tensile    elongations at break and 100% moduli were measured by the methods    described previously. The results are shown in Table 10 below.

COMPARATIVE EXAMPLES 31-33

-   (1) Using the pellets alone, a press film and a molded article    (specimen) were prepared by the method described previously.-   (2) The oxygen transmission coefficients, elastic moduli, tensile    strengths at break, tensile elongations at break and 100% moduli    were measured by the methods described previously. The results are    shown in Table 10 below.

TABLE 10 Comparative Comparative Comparative Comparative ComparativeExample 29 Example 30 Example 31 Example 32 Example 33 Modified EVOH (C)30 30 100 Elastomer (J-1) 70 100 Elastomer (J-2) 70 100 Oxygentransmission coefficient 67000 58000 2.5 110000 110000 (ml · 20 μm/m² ·day · atm) Elastic modulus (Pa) 2.9 × 10⁷ 3.0 × 10⁷ 9.0 × 10⁸ 8.8 × 10⁶8.6 × 10⁶ 100% modulus (MPa) 7 8 — 2.3 1.9 Tensile strength at break(MPa) 8 9 53 8.5 8.2 Tensile elongation at break (%) 230 210 56 550 520Average diameter of dispersed — — — — — particles (μm)

The results given in Table 9 above show that the use of the resincompositions of Examples 34 to 39, which were produced using modifiedEVOH (C), elastomer (J) and crosslinking agent (K), gives good gasbarrier properties such that the oxygen transmission coefficient rangesfrom 12 to 175 ml·20 μm/m²·day·atm (1.4 to 20 fm·20 μm/Pa·s) and thathigh-quality molded articles superior in various properties such asmechanical properties, flexibility and elasticity are obtained smoothly.

The results given in Table 10 above show that the use of the resincompositions of Comparative Examples 29 and 30, which contain modifiedEVOH (C), elastomer (J) and no crosslinking agent (K), gives poor gasbarrier properties such that the oxygen transmission coefficient rangesfrom 58000 to 67000 ml·20 μm/m²·day·atm (6600 to 7700 fm·20 μm/Pa·s) andthat they are not sufficiently good also in mechanical properties.

INDUSTRIAL APPLICABILITY

According to the present invention, a resin composition superior inbarrier properties, transparency, stretchability, flexibility, flexingresistance and interlayer adhesiveness is provided. The resincomposition is useful as a barrier material and is suitably employed inthe form of various kinds of molded articles, especially multilayerstructures, which are required to have barrier properties.

1. A resin composition comprising: 1-99 wt. % of a modifiedethylene-vinyl alcohol copolymer (C) having an ethylene content of 5-55mole % and comprising 0.3-40 mole % of a following structural unit (I);and 1-99 wt. % of an ethylene-vinyl alcohol copolymer (F) having anethylene content of 5-55 mole % and being free of the structural unit(I):

wherein R¹ and R² are each a hydrogen atom, and wherein one of R³ and R⁴is a methyl group, an ethyl group or a (CH₂)_(i)OH group, wherein i isan integer of 1 or 2, and the other is a hydrogen atom.
 2. The resincomposition according to claim 1, wherein the modified ethylene-vinylalcohol copolymer (C) has an ethylene content of 10-50 mole %.
 3. Theresin composition according to claim 1, wherein the modifiedethylene-vinyl alcohol copolymer (C) has an ethylene content of 20-45mole %.
 4. The resin composition according to claim 1, wherein themodified ethylene-vinyl alcohol copolymer (C) has an ethylene content of25-31 mole %.
 5. The resin composition according to claim 1, wherein themodified ethylene-vinyl alcohol copolymer (C) comprises 0.5-35 mole % ofthe structural unit (I).
 6. The resin composition according to claim 1,wherein the modified ethylene-vinyl alcohol copolymer (C) comprises 1-30mole % of the structural unit (I).
 7. The resin composition according toclaim 1, wherein the modified ethylene-vinyl alcohol copolymer (C)comprises 2-25 mole % of the structural unit (I).
 8. The resincomposition according to claim 1, wherein the modified ethylene-vinylalcohol copolymer (C) has a melt flow rate of 0.1-30 g/10 min whenmeasured at 190° C. under a load of 2160 g.
 9. The resin compositionaccording to claim 1, wherein the modified ethylene-vinyl alcoholcopolymer (C) has a melt flow rate of 0.3-25 g/10 min when measured at190° C. under a load of 2160 g.
 10. The resin composition according toclaim 1, wherein the modified ethylene-vinyl alcohol copolymer (C) has amelt flow rate of 0.5-20 g/10 min when measured at 190° C. under a loadof 2160 g.
 11. The resin composition according to claim 1, wherein themodified ethylene-vinyl alcohol copolymer (C) has a melting point of160° C. or lower.
 12. The resin composition according to claim 1,wherein the modified ethylene-vinyl alcohol copolymer (C) has a meltingpoint of 150° C. or lower.
 13. The resin composition according to claim1, wherein the modified ethylene-vinyl alcohol copolymer (C) has amelting point of 140° C. or lower.
 14. The resin composition accordingto claim 1, wherein the ethylene-vinyl alcohol copolymer (F) has anethylene content of 20-50 mole %.
 15. The resin composition according toclaim 1, wherein the ethylene-vinyl alcohol copolymer (F) has anethylene content of 25-45 mole %.
 16. The resin composition according toclaim 1, wherein the ethylene-vinyl alcohol copolymer (F) has anethylene content of 27-38 mole %.
 17. The resin composition according toclaim 1, wherein the ethylene-vinyl alcohol copolymer (F) has an oxygentransmission rate of not more than 1000 cc·20 μm/m²·day·atm whenmeasured at 20° C. and 65% RH.
 18. The resin composition according toclaim 1, wherein the ethylene-vinyl alcohol copolymer (F) has an oxygentransmission rate of not more than 100 cc·20 μm/m²·day·atm when measuredat 20° C. and 65% RH.
 19. The resin composition according to claim 1,wherein the ethylene-vinyl alcohol copolymer (F) has an oxygentransmission rate of not more than 10 cc·20 μm/m²·day·atm when measuredat 20° C. and 65% RH.
 20. The resin composition according to claim 1,comprising: 1-50 wt. % of the modified ethylene-vinyl alcohol copolymer(C); and 50-99 wt. % of the ethylene-vinyl alcohol copolymer (F). 21.The resin composition according to claim 1, comprising: 5-40 wt. % ofthe modified ethylene-vinyl alcohol copolymer (C); and 60-95 wt. % ofthe ethylene-vinyl alcohol copolymer (F).
 22. The resin compositionaccording to claim 1, comprising: 10-30 wt. % of the modifiedethylene-vinyl alcohol copolymer (C); and 70-90 wt. % of theethylene-vinyl alcohol copolymer (F).
 23. The resin compositionaccording to claim 1, wherein the difference between the ethylenecontent of the modified ethylene-vinyl alcohol copolymer (C) and theethylene content of the ethylene-vinyl alcohol copolymer (F) is 2-30mole %.
 24. The resin composition according to claim 1, wherein thedifference between the ethylene content of the modified ethylene-vinylalcohol copolymer (C) and the ethylene content of the ethylene-vinylalcohol copolymer (F) is 5-20 mole %.
 25. The resin compositionaccording to claim 1, wherein the resin composition has an oxygentransmission rate of not more than 100 cc·20 μm/m²·day·atm when measuredat 20° C. and 65% RH.
 26. The resin composition according to claim 1,wherein the resin composition has an oxygen transmission rate of notmore than 50 cc·20 μm/m²·day·atm when measured at 20° C. and 65% RH. 27.The resin composition according to claim 1, wherein the resincomposition has an oxygen transmission rate of not more than 20 cc·20μm/m²·day·atm when measured at 20° C. and 65% RH.
 28. The resincomposition according to claim 1, wherein the resin composition has anoxygen transmission rate of not more than 10 cc·20 μm/m²·day·atm whenmeasured at 20° C. and 65% RH.
 29. The resin composition according toclaim 1, wherein the resin composition has a carbon dioxide transmissionrate of not more than 500 cc·20 μm/m²·day·atm when measured at 20° C.and 65% RH.
 30. The resin composition according to claim 1, wherein theresin composition has a carbon dioxide transmission rate of not morethan 200 cc·20 μm/m²·day·atm when measured at 20° C. and 65% RH.
 31. Theresin composition according to claim 1, wherein the resin compositionhas a carbon dioxide transmission rate of not more than 100 cc·20μm/m²·day·atm when measured at 20° C. and 65% RH.
 32. The resincomposition according to claim 1, wherein the resin composition has acarbon dioxide transmission rate of not more than 50 cc·20 μm/m²·day·atmwhen measured at 20° C. and 65% RH.
 33. The resin composition accordingto claim 1, wherein the resin composition has a Young's modulus of notmore than 200 kgf/mm² in a tensile strength/elongation measurement at23° C. and 50% RH.
 34. The resin composition according to claim 1,wherein the resin composition has a Young's modulus of not more than 180kgf/mm² in a tensile strength/elongation measurement at 23° C. and 50%RH.
 35. The resin composition according to claim 1, wherein the resincomposition have a tensile strength at yield of 4.0-10.0 kgf/mm² and atensile elongation at break of 200-500% in a tensile strength/elongationmeasurement at 23° C. and 50% RH.
 36. A method of producing the resincomposition according to claim 1, wherein said method comprises:reacting an ethylene-vinyl alcohol copolymer (A) with a monofunctionalepoxy compound (B) having a molecular weight of not more than 500 toproduce the modified ethylene-vinyl alcohol copolymer (C); and blendingthe modified ethylene-vinyl alcohol copolymer (C) with theethylene-vinyl alcohol copolymer (F).
 37. The method according to claim36, wherein the ethylene-vinyl alcohol copolymer (A) has an ethylenecontent of 5-55 mole %.
 38. The method according to claim 36, whereinthe ethylene-vinyl alcohol copolymer (A) has an ethylene content of10-50 mole %.
 39. The method according to claim 36, wherein theethylene-vinyl alcohol copolymer (A) has an ethylene content of 20-45mole %.
 40. The method according to claim 36, wherein the ethylene-vinylalcohol copolymer (A) has an ethylene content of 25-31 mole %.
 41. Themethod according to claim 36, wherein the ethylene-vinyl alcoholcopolymer (A) has an intrinsic viscosity of not less than 0.06 L/g. 42.The method according to claim 36, wherein the ethylene-vinyl alcoholcopolymer (A) has an intrinsic viscosity of 0.07-0.2 L/g.
 43. The methodaccording to claim 36, wherein the ethylene-vinyl alcohol copolymer (A)has an intrinsic viscosity of 0.075-0.15 L/g.
 44. The method accordingto claim 36, wherein the ethylene-vinyl alcohol copolymer (A) has anintrinsic viscosity of 0.080-0.12 L/g.
 45. The method according to claim36, wherein the ethylene-vinyl alcohol copolymer (A) has a melt flowrate of 0.1-30 g/10 min when measured at 190° C. under a load of 2160 g.46. The method according to claim 36, wherein the ethylene-vinyl alcoholcopolymer (A) has a melt flow rate of 0.3-25 g/10 min when measured at190° C. under a load of 2160 g.
 47. The method according to claim 36,wherein the ethylene-vinyl alcohol copolymer (A) has a melt flow rate of0.5-20 g/10 min when measured at 190° C. under a load of 2160 g.
 48. Themethod according to claim 36, wherein the monofunctional epoxy compound(B) having a molecular weight of not more than 500 is selected from thefollowing formulae (III) or (IV):

wherein one of R⁵ and R⁶ is a methyl group or an ethyl group, and theother is a hydrogen atom, and wherein R⁷ is a hydrogen atom, and i is aninteger of 1 or
 2. 49. The method according to claim 36, wherein themodified ethylene-vinyl alcohol copolymer (C) is produced by reactingthe ethylene-vinyl alcohol copolymer (A) with the monofunctional epoxycompound (B) in a weight ratio of 100:1-50.
 50. The method according toclaim 36, wherein the modified ethylene-vinyl alcohol copolymer (C) isproduced by reacting the ethylene-vinyl alcohol copolymer (A) with themonofunctional epoxy compound (B) in a weight ratio of 100:2-40.
 51. Themethod according to claim 36, wherein the modified ethylene-vinylalcohol copolymer (C) is produced by reacting the ethylene-vinyl alcoholcopolymer (A) with the monofunctional epoxy compound (B) in a weightratio of 100:5-35.
 52. The method according to claim 36, wherein themodified ethylene-vinyl alcohol copolymer (C) is produced by reactingthe ethylene-vinyl alcohol copolymer (A) with the monofunctional epoxycompound (B) in a solution.
 53. The method according to claim 52,wherein said reacting is conducted at a temperature of from roomtemperature to 150° C.
 54. The method according to claim 52, whereinsaid reacting is conducted in the presence of a polar aprotic solventselected from dimethylsulfoxide, dimethylformamide, dimethylacetamideand N-methylpyrrolidone.
 55. The method according to claim 52, whereinsaid reacting is conducted in the presence of a reaction catalystselected from acid catalysts and alkali catalysts.
 56. The methodaccording to claim 52, wherein the reaction catalyst is present in anamount of 0.0001-10 wt. %, based on 100 wt. % of the ethylene-vinylalcohol copolymer (A).
 57. The method according to claim 36, wherein themodified ethylene-vinyl alcohol copolymer (C) is produced by reactingthe ethylene-vinyl alcohol copolymer (A) with the monofunctional epoxycompound (B) in an extruder.
 58. The method according to claim 57,wherein the extruder is selected from a single-screw extruder, atwin-screw extruder, and a multi-screw extruder.
 59. The methodaccording to claim 57, wherein said reacting is conducted at atemperature of about 180-300° C.
 60. The method according to claim 57,wherein said reacting is conducted under a pressure of 0.5-30 MPa. 61.The method according to claim 57, wherein said reacting is conducted inthe presence of a reaction catalyst, which is a metal salt comprising: ametal cation selected from groups 3-12 of the periodic table; and ananion.
 62. The method according to claim 61, wherein the metal cation isselected from zinc, yttrium and gadolinium.
 63. The method according toclaim 61, wherein the anion is a monovalent anion, the conjugate acid ofis as strong as or stronger than sulfuric acid, and is selected fromsulfonate ions, halide ions, perchlorate ions, anions having four ormore fluorine atoms, ions of tetraphenylborate derivatives, and ions ofcarborane derivatives.
 64. The method according to claim 61, wherein thereaction catalyst is present in an amount of 0.1-20 μmol/g based on theweight of the ethylene-vinyl alcohol copolymer (A).
 65. The methodaccording to claim 61, wherein the reaction catalyst is present in anamount of 0.5-10 μmol/g based on the weight of the ethylene-vinylalcohol copolymer (A).
 66. A resin composition comprising: 1-99 wt. % ofa modified ethylene-vinyl alcohol copolymer (C) having an ethylenecontent of 5-55 mole % and comprising 0.3-40 mole % of a followingstructural unit (I); and 1-99 wt. % of an ethylene-vinyl alcoholcopolymer (F) having an ethylene content of 5-55 mole % and being freeof the structural unit (I):

wherein R¹ and R² are each a hydrogen atom, wherein one of R³ and R⁴ isa methyl group, an ethyl group or a (CH₂)_(i)OH group, wherein i is aninteger of 1 or 2, and the other is a hydrogen atom, and wherein saidresin composition is produced by a process comprising: reacting anethylene-vinyl alcohol copolymer (A) with a monofunctional epoxycompound (B) having a molecular weight of not more than 500 to producethe modified ethylene-vinyl alcohol copolymer (C); and blending themodified ethylene-vinyl alcohol copolymer (C) with the ethylene-vinylalcohol copolymer (F).